Liquid metal dispersed single-atom catalyst with high-temperature stability

Domain: biology
Published: 2026-03-13
Editorial outcome: major_revision

Abstract
Single-atom catalysts (SACs) enable greener and more economically sustainable chemical production by significantly improving thermocatalysis efficiency and selectivity through maximized atom utilization and highly homogeneous metal coordination environments. Unfortunately, SACs are fundamentally constrained by the stability owing to the severe aggregation of single atoms, especially under the high-temperature thermocatalysis operations, which compromises the overall catalytic performance. Here, we report a synthetic strategy to realize the highly thermal-stable SACs resistance to sintering at harsh conditions through harnessing the inherent metal affinity and fluidity of liquid metal. A stable liquid metal-active metal interaction is formed, profiting from the superior metal affinity of liquid metal. Combined with the fluidity of liquid metal, active metal atoms can move but remain confined to the liquid metal as the metallic single-atom state at high temperatures. This catalyst exhibits outstanding thermal durability for ethane dehydrogenation, sustaining stable operation for over 100 h at 650 oC with an impressive ethylene selectivity of 98%. The strategy of constructing stable metal-metal interactions by utilizing the inherent metal affinity and dynamic fluidity of liquid metal will pave a practical way for the design of highly thermal-stable SACs.

Introduction
Industrial thermocatalysis holds great promise for improving the efficiency and sustainability of thermochemical processes and producing value-added chemicals in the modern chemical industry1–3. Single-atom catalysts (SACs) have garnered extensive attention for the development of highly efficient, sustainable, cost-effective catalysts in thermocatalysis fields due to their maximized atom utilization and highly homogeneous metal coordination environment4–8.

However, constructing highly thermally durable SACs is a significant challenge in industrial applications. This is owing to the inherently ultra-high surface energy of single atoms, and the high temperature (> 300 oC) provides enough energy to overcome the diffusion barrier of single atoms, leading to the migration of single atoms and severe agglomeration9. In the current paradigm, it is prevalent to stabilize SACs by modulating supports (such as carbon-based supports10, metal oxides characterized by defection11–14, and so on) that tune interactions between metal atoms and supports. However, the presence of a strong bonding interaction between the supports and the single atoms may result in the compromise of the unique coordination structure of the single atoms, thereby diminishing the catalytic activity and even deactivation15,16. In terms of the strategy of using porous supports to spatially confine single atoms (such as molecular sieves and metal-organic frameworks)17,18, surmounting the substantial surface energy of the single atoms is still difficult, which will lead to inevitable aggregation of single atoms at elevated temperatures19,20. Hence, designing an optimal support that balances metal-support interaction for realizing highly efficient thermal-stable SACs remains an obstacle.

Inspired by the rule of thumb “like dissolves like”, it is promising to take advantage of unique metal-metal interaction to efficiently disperse active metals to acquire stable single atoms with inherently high metal activity by using the liquid metal as the dispersion21–23. Herein, we achieve the highly efficient dispersion of single atoms with unprecedented thermal stability by utilizing the inherent fluidity and metal affinity of liquid metal. As a demonstration, gallium (Ga), capable of an ideal liquid environment, was employed to spontaneously disperse active metal platinum (Pt). Exceptionally thermal-stable Pt single atoms dispersed by Ga that survived at 650 oC were realized. In this system, profiting from the superior metal affinity of Ga with Pt, Pt–Pt bonds are broken at elevated temperatures, and subsequently the mobile Pt atoms are captured by Ga to form the stable Pt–Ga interaction, accomplishing the highly efficient dispersion of Pt single atoms. The fluidity of liquid metal and the stable Pt–Ga interaction ensure that the Pt atoms can remain dynamically scattered throughout the whole liquid metal dispersion system. Additionally, liquid metal dispersed single atoms can self-update onto the catalysis interface continuously, promoting catalytic reactions at the interface. Hence, these liquid metal dispersed SACs manifested remarkable thermal durability for ethane dehydrogenation (EDH), sustaining stable operation for over 100 hours at 650 oC with ethylene selectivity of 98%. Furthermore, the elemental composition of the system was extended to other noble metals, demonstrating the universality of the synthetic strategy. This elucidates the promising potential in realizing highly thermal-stable SACs.

Results
The design of thermal-stable liquid metal dispersed SACs

With increasing temperature, the diffusivity of single atoms is accelerated, thereby enhancing their migration and subsequent aggregation into larger clusters or particles due to thermodynamics favoring lower total surface energy states9,24. In essence, the competition of aggregation reflected the competitive bonding between single atom/single atom and single atom/support. Establishing highly efficient as well as stable metal-support interaction is crucial for blocking the aggregation and sintering of single atoms at high temperatures. In this work, we make the realization of thermal-stable SACs by utilizing liquid metal to disperse and stabilize active metals (Fig. 1a). The abundance of metallic bonds in the liquid metal makes it an ideal medium for effectively dispersing active metals with similar metallic bonds, and the active metals can keep the metallic state. At elevated temperatures, enough energy is provided to break metallic bonds in the active metals. Furthermore, the fluidity of liquid metals drives the dispersion of active atoms in liquid metals at elevated temperatures. These dynamically migrating single atoms can be subsequently combined with liquid metal, profiting from its good metallic affinity and forming a stable interaction between these two kinds of atoms. In light of this, equipped with the naturally metallic affinity and fluidity of liquid metal, the highly thermal-stable SACs can be realized.

The liquid metal dispersed SACs are synthesized by dissolving Pt nanoparticles into liquid Ga at elevated temperatures. The mechanism illustrating the formation process of the liquid metal dispersed SACs is shown in Fig. 1a. Firstly, the Pt particles were sprinkled evenly over the liquid metal. As the temperature gradually increases, the solubility of the active metal in the dispersion is further increased, and the active metal can efficiently disperse in the liquid metal within its limited solubility. The Pt−Pt bonds in the original Pt metal nanoparticles are broken and tend to bind tightly to Ga atoms and form a thermodynamically stable configuration with Ga atoms, benefiting from the good affinity between Ga and Pt. The stable Pt−Ga interaction curtails the sintering of Pt single atoms. Moreover, according to the Arrhenius equation25, the thermal motion of atoms would be intensified by high temperature, promoting the rapid diffusion between Pt and Ga atoms and the continuous renewal of Pt single atoms exposed on the catalytic surface (Fig. 1b). In contrast, when single atoms are anchored to solid supports, their co-migration with the supports becomes kinetically constrained. Once the metal-support interactions become insufficient to compensate for the inherently high surface energy of single atoms, these atoms tend to detach from the solid supports and aggregate. This process is exothermic, where minimization of total surface energy governs particle growth26. Meanwhile, some single atoms may embed into the lattice of supports, becoming buried when the interaction between the support and metal atoms is too strong. These lead to the loss of active sites, reducing the stability of SACs and consequently affecting their activity and selectivity (Fig. 1c).

Thermal stability of active metal atoms mono-dispersed in liquid Ga

Ab initio molecular dynamics (AIMD) simulations were employed to elucidate the atomic-scale dispersed state of active metal in liquid metal (computational details are provided in the supplementary information). Using Pt as a model of Pt cluster, we investigated the structural evolution of both clustered and dispersed Pt in liquid Ga during 10 ps simulations at 923 K (Figs. 2a, b and Supplementary Movs. 1, 2). The calculated total energy versus time curves for the Ga Pt system containing clustered Pt and dispersed Pt (Fig. 2c) reveal that the dispersed Pt generally exhibits lower total energy compared to the aggregated Pt clusters within the simulated 10 ps. The results indicate that the remarkable atomic diffusion of liquid Ga metal at high temperature promotes the migration of heterogeneous active metal atoms, thereby stabilizing their dispersed atomic state in liquid Ga.

The relatively high Pt concentration in the Ga Pt system leads to intermittent formation of Pt dimer, as evidenced by the time-dependent curve of the shortest Pt–Pt distance (Supplementary Fig. 1). To further elucidate the actual existence state of Pt atoms in liquid Ga, we performed AIMD simulations of the Ga Pt system (a Pt dimer embedded in Ga ) at 923 K. The 10 ps NVT ensemble simulations (Fig. 2d) display that the Pt–Pt interatomic distance progressively increases from 4.18 Å to 11.63 Å, significantly exceeding the Pt–Pt bond length of 2.65 ~ 2.79 Å28. This unequivocally confirms that Pt atoms preferentially exist as monatomic species in the liquid Ga (Supplementary Fig. 2 and Supplementary Movs. 3, 4). Further statistical analysis of the coordination environment of Pt atoms in the Ga Pt system shows that the dominant coordination numbers for individual Pt atoms are 8 or 9 (Supplementary Figs. 3, 4), implying that mono-dispersed Pt atoms migrate within liquid Ga in the form of clusters such as Ga Pt or Ga Pt (Supplementary Fig. 5).

To fundamentally understand the thermodynamic preference for Pt mono-dispersion in liquid Ga, we systematically calculated the bond energy difference ∆E (∆𝐸 = 𝐸 + 𝐸̅ −2𝐸 ) only for the Pt , (Ga Pt) , (Ga Pt) , and (Ga Pt) molecular clusters (Fig. 2e and Supplementary Figs. 6 ~ 11). Here, 𝐸̅ represents the average Ga–Ga bond energy in the Ga molecular clusters, 𝐸 denotes the Pt–Pt bond energy in the (Ga Pt) molecular clusters, and 𝐸 refers to the Ga–Pt bond energy in the Ga Pt molecular clusters. The results indicate that the ∆E values for the Pt , (Ga Pt) , (Ga Pt) , and (Ga Pt) molecular clusters, evaluated using different computational methods (B3LYP, MN15L, and M06L), are all greater than zero. This demonstrates that in these molecular systems, the Ga atoms involved in bond-breaking readily disrupt the Pt–Pt bonds, leading to the formation of stable Pt–Ga–Pt bridging units, thereby promoting the single-atom dispersion of Pt in liquid Ga. Meanwhile, we calculated the formation energies of Pt Ga, (Ga Pt) Ga, and (Ga Pt) Ga molecules, which were determined to be 101.1, 46.2, and 57.9 kcal mol–1, respectively (Supplementary Fig. 12 and Fig. 2f). Additionally, we roughly estimated the energy barriers of Ga atom insertion into the Pt–Pt bond to be 58.2, 13.4, and 40.2 kcal mol–1 by performing rigid scans of the Pt–Ga–Pt angle (Supplementary Fig. 13 and Fig. 2f). These results clearly demonstrate that, both thermodynamically and kinetically, Ga atoms in liquid Ga at 923 K can readily disrupt Pt–Pt bonds, thereby promoting the mono-dispersion of Pt atoms.

To more intuitively demonstrate the mono-dispersion state of Pt atoms in Ga, we constructed Ga Pt and Ga Pt structures with Pt contents of 2 at% and 0.2 at%, respectively (Supplementary Fig. 14). Meanwhile, based on a training dataset containing 17347 structures and a test dataset of 1926 structures, we trained a Ga–Pt neuroevolution potential model (Supplementary Fig. 15). The consistency between the calculated and experimental solubility validates the effectiveness of the constructed machine learning force field in evaluating the dissolution of Pt in liquid Ga (Supplementary Fig. 16). Subsequently, we performed 20 ns NVT molecular dynamics simulations at 923 K on the Ga Pt and Ga Pt structures using the trained Ga–Pt machine-learning potential. The simulation results clearly indicate that the Pt cluster rapidly disperse in liquid Ga (Supplementary Fig. 17). Furthermore, we analyzed the proportions of mono-dispersed and dimerized Pt states in all structures over the last 10 ns (Fig. 2g). In the Ga Pt structure, the proportion of mono-dispersed Pt was 98.2%, while in the Ga Pt structure, it reached 99.9%. The results clearly demonstrate that in structures with Pt content of 2 at% or below, Pt atoms can be considered fully mono-dispersed at 923 K. Moreover, the calculated average numbers of surface atoms in the Ga Pt and Ga Pt structures are 5.4 and 3.0, respectively (Supplementary Fig. 18 and Supplementary Fig. 19), and the temporal evolution of the vertical migration of individual Pt atoms and their probability distribution demonstrate a preferential tendency to migrate toward the surface (Supplementary Fig. 20). These indicate that a certain proportion of mono-dispersed Pt atoms can continuously exist on the liquid surface and participate in relevant catalytic reactions. Overall, the stable Ga Pt and similar clusters that are formed profited from the favorable affinity between Ga and Pt inhibit the aggregation and sintering of Pt during thermal motion, laying the foundation for synthesizing the highly thermal-stable SACs.

Characterization of liquid catalyst

To further validate that liquid metal can act as the dispersion for single atoms, we synthesized the Ga-dispersed Pt SACs (Pt SACs@Ga). The detailed structure of the catalyst was characterized by transmission electron microscopy (TEM) and energy dispersive spectrometry (EDS). The Pt species in the liquid metal exists in a mono-disperse distribution without the obvious occurrence of aggregated Pt (Fig. 3a). The bright-field image of Pt SACs@Ga liquid catalyst maintains an almost invariant brightness across the whole particle and the corresponding selected area electron diffraction (SAED) data shows no diffraction spots of Pt in the amorphous ring, revealing the lack of long-range order structure in the Ga–Pt catalyst (Supplementary Fig. 21 and Fig. 3b). Furthermore, the X-ray photoelectron spectroscopy (XPS) spectrum was employed to reveal the chemical composition and electronic structure of the liquid metal dispersed SACs. Before the execution of XPS measurements, the sample underwent etching with argon ions to eliminate the natural oxide layer and surface contaminants. Ga 2p peaks appear at 1116.73 eV and 1116.59 eV (Fig. 3c), which are consistent with the reported binding energies of metallic Ga (Ga0 2p =1116.70 eV). Meanwhile, due to the higher electronegativity of Pt (2.28) than that of Ga (1.81)29, the Pt in the Pt SACs@Ga system served as the electron acceptor, and the Pt 4f and 4f peaks in Pt SACs@Ga exhibit a positive shift (1.0 eV) than those in pure Pt metal (Fig. 3d). It is a consensus that metallic Pt0 species occupy a preeminent role as the active sites for many catalytic processes30–32. This guarantees a proficient and robust distribution of single atoms while preserving their catalytic activity. Furthermore, the absence of the obvious aggregation of Pt atoms in the Pt SACs@Ga is further identified by X-ray diffraction (XRD) tests, where no signal of Pt (PDF#04-0802) is observed (Supplementary Fig. 22). To mitigate the potential inaccuracies arising from the insensitivity of XRD to small Pt clusters, the pair distribution function (PDF) analysis was conducted to delve into the interatomic structure of the Pt SACs@Ga liquid catalyst (Supplementary Fig. 23). The absence of Pt–Pt bonds indicates that Pt is distributed nearly at the atomic level within the liquid Ga without the formation of Pt clusters. These observations suggest that liquid metal can achieve the efficient uniform dispersion of highly active single atoms at elevated temperatures.

To further verify the exact dispersion state of Pt in the Pt SACs@Ga catalyst, X-ray absorption spectroscopy (XAS) measurements were conducted. The X-ray absorption edge near-edge structure (XANES) spectrum shows that the intensity of the white line at the L edge of Pt lies between that of the Pt foil and that of PtO . Correspondingly, the k -weighted R-space Fourier transformed spectra of the extended X-ray absorption fine structure spectra (EXAFS) show the prominent peak at 2.14 Å for Pt SACs@Ga distinguished from that of the Pt–O (1.62 Å) bonds for PtO and the Pt–Pt bonds (2.24 Å) for Pt foil (Fig. 3f). All these results intuitively indicate that the Pt exists in the single-atom state in liquid metal.

EDH performance of liquid metal dispersed SACs

Based on the computational results, the liquid metal dispersed SACSs theoretically feature excellent thermal stability at high temperatures. It is necessary to conduct specific high-temperature tests for verification. Pt-based catalysts are used for the dehydrogenation of alkanes due to their high efficiency in activating the C−H bonds of alkanes and low propensity in breaking C−C bonds33,34. And Pt−Sn/Al O (Oleflex process) is the primary industrial technology operated for direct propane dehydrogenation35. While it suffers from severe sintering and coke, which results in rapid deactivation and restricts the selectivity36. Therefore, as a proof of concept, the thermal stability of liquid metal dispersed SACs was validated by EDH. As shown in Fig. 4a, when exposed to ethane, Pt single atoms exposed on the surface capture ethane molecules and synergistically activate C–H bonds, leading to selective EDH to ethylene. Meanwhile, the fluidic characteristic of liquid metal dispersed SACs at operating conditions enables continuous replenishment of catalytically active Pt atoms onto the surface. The stable interaction between Pt−Ga effectively blocks the aggregation of Pt atoms during the constant migration. Benefiting from the advantages mentioned above, these adaptive surface active sites maintain long-term activity and thermal stability.

To circumvent the issue of inadequate interaction between the liquid metal dispersed SACs and the reaction gas, the porous support is utilized to amplify the gas mass transfer rate. So, we coupled liquid metal dispersed SACs with porous MFI zeolite (ZSM-5) by the physical approach of ultrasonication to increase the contact surface area between the liquid metal support SACs and gas reactants. As demonstrated in Supplementary Fig. 24, EDS mappings revealed a well-distribution of Ga, Si, and Al, indicating the liquid metal is uniformly loaded in the ZSM-5 zeolite framework. Upon heating, Pt will be spontaneously dispersed in Ga homogeneously, achieving the preparation of a zeolite-dispersed liquid metal supported SACs (Pt SACs@Ga/ZSM-5). Further, we performed in situ XRD to explore the dispersing process of Pt (Supplementary Fig. 25). The diffraction peak observed at 43 ~ 47o originates from the carbon in situ reactor (Supplementary Fig. 26). Initially, the characteristic peaks of Pt can be apparently observed, which are located at 39.76o and 46.24o. With the temperature increasing, the characteristic peaks of Pt were gradually weakened and disappeared subsequently, proving the dispersion of Pt particles.

The catalytic performance was evaluated in non-oxidative EDH at 923 K in a fixed-bed quartz U-tube reactor under atmospheric pressure with a feed gas of 12.5 vol% C H in Ar. The Pt particles/ZSM-5 catalyst, which is synthesized by direct mixing commercial Pt particles with ZSM-5, exhibits ethane conversion at 9.5% and ethylene selectivity at 82.6% (Figs. 4b, c). Interestingly, the liquid metal dispersed SACs are highly active with ethane conversion at 17.8% and ethylene selectivity at 98.3%. This is because the introduction of liquid metal alters the state of Pt. By dispersing Pt particles into single Pt atoms, the utilization of Pt atoms is maximized to achieve high conversion rates. Furthermore, since the size of Pt particle significantly influences catalytic performance, larger Pt nanoparticles typically promote C−C cleavage and deep dehydrogenation side reactions37. In contrast, Pt-based catalysts dispersed at the atomic scale exhibit excellent selectivity for ethylene due to their superior activation of C−H bonds in alkanes, while simultaneously limiting C−C bond cleavage to prevent dehydrogenation reactions. Therefore, when liquid metal is introduced, Pt exists in a single-atom state, enabling the Pt SACs@Ga/ZSM-5 catalyst to achieve high selectivity. To verify the universality of the strategy that liquid metals can disperse metals into single atoms, we extended the synthesis approach to other systems and successfully synthesized liquid metal dispersed Rh SACs (Supplementary Fig. 27). Moreover, Rh SACs@Ga/ZSM-5 exhibits significantly improved catalytic performance compared to Rh particles/ZSM-5 in EDH (Supplementary Fig. 28).

To gain a deeper understanding of the effects of liquid metal dispersed SACs and nano catalysts on the dehydrogenation reaction of ethane, we conducted kinetic studies on both types of catalysts. We measured the ethane conversion in a temperature range of 883 ~ 933 K and fitted the data according to the Arrhenius equation to calculate the apparent activation energy for EDH. The apparent activation energies for Pt SACs@Ga/ZSM-5 and Pt particles/ZSM-5 are 102.44 kJ mol−1 and 137.18 kJ mol−1, respectively (Supplementary Fig. 29). The significantly reduced activation energy indicates a decreased energy barrier that needs to be overcome for the reaction to proceed. And the single Pt atom dispersed in the liquid Ga can more effectively weaken the C–H bond of ethane than Pt particles. Therefore, the Pt SACs@Ga/ZSM-5 catalyst exhibits superior catalytic performance.

The performance of the liquid metal dispersed SACs in the durability test is presented in Fig. 4d. It exhibits sustainable conversion and selectivity in the continuous reaction for 100 h, where the constant ethane conversion of ~18% is obtained without attenuation. And liquid metal dispersed SACs exhibit a steady ethene productivity of around 14.3 g g −1 h−1 during the 100 h Pt EDH test. The catalyst displays no deactivation trend during the testing period, indicating a reasonable expectation of more durable stability. Notably, the XANES spectrum and R-space of liquid metal dispersed SACs after 100 h EDH at Pt L -edge are similar to those of pristine liquid SACs (Figs. 4e, f and Figs. 3e, f), demonstrating exceptional structural integrity under prolonged thermal catalysis. The catalytic performance and structural characterization together confirmed the superior thermal stability of liquid metal dispersed SACs in extremely high temperatures, which remarkably outperforms the traditional solid support loaded SACs. To further substantiate the thermal stability performance of our work, comparing the catalytic reaction temperatures and time on stream of Pt SACs@Ga/ZSM-5 with reported SACs (Supplementary Tab. 1), where the results remain outstanding. The excellent stability, selectivity, and conversion indicate the potential of liquid metal dispersed SACs for reactions limited in harsh conditions.

Methods
Chemicals and materials

Gallium (Ga, 99.999%) was purchased from Shanghai Minor Metals Co. Ltd., platinum (Pt, 99.9%) and molecular sieve (ZSM-5 zeolites, Si/Al = 45) were purchased from Aladdin Industrial Inc. Rhodium (Rh, 99.95%) powder was purchased from Shanghai Macklin Biochemical Co., Ltd. High-purity ethane (99.99%) was purchased from Wuhan Xiangyun Gas Technology Co., Ltd. and was purified using 4A zeolite before reaction.

Catalyst synthesis

Synthesis of liquid metal dispersed SACs

The liquid metal dispersed SACs were synthesized by dissolving Pt or Rh nanoparticles into molten Ga in a tube furnace in a H /Ar mixture gas at 650 oC, with a heating rate of 5 oC min–1.

Synthesis of the catalyst for EDH

In order to increase the mass transfer of the ethane, the liquid metal is coupled with the ZSM-5 (Ga/ZSM-5) by sonication as follows. The liquid Ga and ZSM-5 zeolites were transferred to ethylene glycol, and the solution was sonicated by a probe-type sonicator for 2 h (5 s on and 3 s off) at a power of 290 W. After sonication, the resultant precipitations were washed with ethanol and water 3 times. And then the resultant was flash frozen in liquid nitrogen for five minutes and freeze-dried at −40 oC, under a pressure less than 200 mTorr, for 24 h using the FreeZone 4.5 Liter Benchtop Freeze Dry System. The Pt particles were mixed with Ga/ZSM-5 (or pure ZSM-5) and heated from room temperature to 650 oC at a rate of 10 oC min–1 in the reactor under a H /Ar mixed gas atmosphere. The mixture was then held at 650 oC for 30 minutes to complete the synthesis of the Pt SACs@Ga/ZSM-5 catalyst (or Pt particles/ZSM-5). The Pt : Ga atomic ratio of the Pt SACs@Ga/ZSM-5 catalyst prepared for catalytic testing was maintained at 0.2 : 99.8. After purging the H from the U-tube, the catalyst was ready for catalytic testing. Similarly, replace the Pt particles with Rh particles and undergo the same treatment to obtain Rh SACs@Ga/ZSM-5 (or Rh particles/ZSM-5), and the Rh : Ga atomic ratio of the Rh SACs@Ga/ZSM-5 catalyst used for catalytic testing is also maintained at 0.2 : 99.8.

Catalyst characterizations

The morphology of the liquid metal dispersed SACs was characterized by an F200 transmission electron microscope (TEM) (JEOL, Japan) operated at 200 kV. X-ray diffraction (XRD) data was employed by PANalytical X’Pert-Pro diffractometer, with a Cu K𝛼 radiation (𝜆 = 0.15406 nm), in the 2θ scan mode ranging from 10o to 80o at a scan speed of 8o min−1. In situ XRD was collected with the Rigaku Ultima Ⅳ instrument using Cu Kα (λ = 1.5406 Å) radiation at 40 kV and 40 mA, and the operating voltage and current were 40 kV and 40 mA, respectively. The catalysts were scanned at a rate of 8o min−1 in the 2θ range of 35o ~ 60o. Pair distribution function (PDF) analysis was performed at room temperature in an air atmosphere by SmartLab, with a Ag K𝛼 radiation (𝜆 = 0.056088 nm). X-ray photoelectron spectroscopy (XPS) measurements were taken on a high-resolution Thermo Fisher Scientific ESCALAB Xi+ spectrometer using Al K𝛼 radiation under vacuum. Pt L and Rh K edge XAFS spectra were collected at the BL11B beamline of the Shanghai Synchrotron Radiation Facility (SSRF). During the measurement, the synchrotron radiation ring was operated at 3.5 GeV, and the electron current was 200 mA in the top-up mode. The samples were sealed in Kapton film. For the measurement of Pt L edge, the white light was monochromatized by a Si (111) double-crystal monochromator. And the white light was monochromatized by a Si (311) double-crystal monochromator when the Rh K edge was measured. The corresponding metal foils were used as a reference sample to calibrate and measure in the transmission mode. All XAFS spectra were processed using the IFEFFIT package. The elemental composition of the samples before and after the reaction was determined by inductively coupled plasma-atomic emission spectroscopy (ICP-OES).

Catalytic performance and kinetic behavior measurements

EDH tests were performed under atmospheric pressure in a fixed-bed quartz U-tube reactor. Catalysts were weighed and loaded into 10 mm outside diameter, 8 mm interior diameter U-tube reactor. 5 sccm of argon and 15 sccm of hydrogen were flowed at 650 oC for 10 minutes to reduce any metal oxides. And then the reactor was purged with 20 sccm argon for 5 min to prevent hydrogen residue. The EDH reaction was conducted in a C H /Ar mixture gas (Vol C H /Vol Ar = 1:7) with a flow rate of 20 mL min−1. The outlet gas products were observed by an online mass spectrometer (Pro-tech, PM-QMS, China ). The conversion of ethane and selectivity to all carbonaceous products (including coke) were calculated as follows:

Ethane conversion = (molar flow rate of carbon (C) in products / molar flow rate of total C in effluent (C H +products)) * 100% (1)

Product selectivity = (molar flow rate of C in product i / molar flow rate of C in all products) * 100% (2)

The kinetic behavior of the catalyst for EDH needs to minimize transport limitations. Therefore, the conversion was limited to 5 ~ 15% while ethylene selectivity remained above 90% by systematically varying the catalyst amount. By analyzing the temperature and pressure dependence of these rates, we extracted the activation energy and reaction order for the reaction.

Theoretical calculations

Quantum chemistry calculations and Ab initio molecular dynamics simulations

To investigate the atomic-level dispersion of active metals in the liquid Ga, we initially constructed a Ga Pt cubic cell model using LAMMPS-17Apr2024 software. The initial cell parameter was set to 13 Å, with Pt as a cluster molecule and the remaining 90 Ga atoms randomly distributed. Subsequently, ab initio molecular dynamics simulations were performed using the Vienna ab initio simulation package (VASP.5.4.4) to the potential energy curves for both clustered and dispersed states of Pt in the Ga Pt structural model at 923 K. For the dispersed state, the damping coefficients for Ga and Pt were set to 10 and 5, respectively, while for the clustered state, they were set to 10 and 1000. All calculations were conducted using the GGA-PBEsol functional38 and employed the Langevin thermostat and ParrinIello-Rahman method39,40 for the isothermal-isobaric (nP T) ensemble. The cutoff energy was set to 400 eV with an energy convergence tolerance of 10–6 eV, and the simulation time was 10 ps. Due to the relatively high Pt content in the Ga Pt system, occasional Pt units were observed in the simulation results. Therefore, we further performed similar ab initio molecular dynamics simulations for the Ga Pt system, and an extra 10 ps NVT MD simulation was carried out starting from the last snapshot of the NPT simulation. Additionally, the crystalNN statistical method41 was used to evaluate the Pt–Pt bonding in liquid Ga. To gain further insight into the dispersion of Pt atoms in liquid Ga, we employed the B3LYP/LANL2DZ, MN15L/LANL2DZ42 and M06L/LANL2DZ methods to calculate the bond energy difference ∆E . The specific calculation method of ∆E for the Pt , (Ga Pt) , (Ga Pt) , and (Ga Pt) molecular clusters is based on Equation (3):

∆𝐸 = 𝐸 + 𝐸̅ −2𝐸 (3)

Here, 𝐸̅ represents the average Ga–Ga bond energy in the Ga molecular clusters, 𝐸 denotes the Pt–Pt bond energy in the (Ga Pt) molecular clusters, and 𝐸 refers to the Ga–Pt bond energy in the Ga Pt molecular clusters. All bond energy calculations were corrected for basis set superposition error (BSSE). Furthermore, we constructed cluster structures such as Pt , (Ga Pt) , (Ga Pt) , Pt Ga, (Ga Pt) Ga, and (Ga Pt) Ga, optimizing all cluster molecules using the B3LYP/LANL2DZ method. Additionally, we performed rigid scans of the PtGaPt angle in the Pt Ga, (Ga Pt) Ga, and (Ga Pt) Ga cluster systems to roughly estimate the energy barrier associated with the incorporation of Ga atoms into the Pt–Pt bond.

Ga–Pt machine learning force field training and molecular dynamics simulations

We constructed a dataset for the Ga–Pt binary system, comprising 17347 training structures and 1926 test structures. These structures cover bulk and surface structures of α-Ga, β-Ga, γ-Ga, Pt, Ga Pt, Ga Pt, Ga Pt , Ga Pt and Ga Pt , Ga–Pt bulk structures with varying compositions (Ga Pt , Ga Pt , Ga Pt , Ga Pt , Ga Pt , Ga Pt , Ga Pt , Ga Pt , Ga Pt , Ga Pt , Ga Pt , Ga Pt , Ga Pt , Ga Pt , Ga Pt , Ga Pt , Ga Pt , Ga Pt , Ga Pt , and Ga Pt ). Nanoparticle systems such as Pt , Pt , Pt , and Pt were also considered. The dataset was initially generated using isothermal–isobaric (NPT) Ab initio molecular dynamics (MD) simulations under ambient pressure (0.0001 GPa) and temperatures ranging from 0 to 9000 K. A machine learning potential was trained using data from AIMD simulations.

Density functional theory calculations

Density functional theory (DFT) calculations were performed using the Vienna Ab initio Simulation Package (VASP). The calculations employed a plane-wave basis set with the projector augmented-wave (PAW) method and standard pseudo-potentials for Ga and Pt. The GGA-PBE sol density functional was selected, along with D3 dispersion interaction corrections. All calculations were conducted in high-precision mode (PREC = Accurate), with a plane-wave cutoff energy set to 400 eV and without symmetry constraints (ISYM = 0). To ensure accuracy, the electronic self-consistent loop converged to a tolerance of 10–6 eV (EDIFF = 1.0E–6). The Methfessel-Paxton first-order smearing method (ISMEAR = 1) was applied. The conjugate gradient algorithm was used for electronic minimization, and the maximum number of steps for electronic self-consistent (SCF) cycles was set to 999. A k-point mesh was automatically generated based on the reciprocal lattice vectors of the unit cell, with a k-point spacing of approximately 0.040 Å–1 in each direction. Only single-point calculations were performed, as the DFT computations were primarily used to generate labels for training data.

Machine learning force field training

The training of the force field is performed using the efficient Neural Evolutionary Potential (NEP) method and the GPUMD code. The training dataset is sourced from the previously completed PBE -D3 calculations. The cutoff radii for the radial and angular descriptors are set to 8 Å and 6 Å, respectively. The weights for energy, force, and virial stress are 1.0, 1.0, and 0.1, respectively. The number of neurons in the hidden layer of the neural network (NN) is 50. The NEP potential function underwent 200,000 optimization iterations over the entire training set. The final results include the root mean square errors (RMSE) of energy and atomic forces.

Peer review rounds
[{"round": 1, "reviewer_comments": {"reviewer_1": "The work by Ziyue Zeng's and coworkers deals with a very relevant topic in the field of catalysis. The paper is well written and contains relevant information. However, the paper is not suitable for Nature Communications and needs to be fundamentally revised in order to be suitable for a more specialised journal in the future. The reason is simple: the main claims of the article, namely that a single Pt atom can be stabilised in liquid gallium to perform high-temperature dehydrogenation catalysis in the form of supported liquid metal catalysis, are by no means new, but have already been published (with slightly different terminology) in more than 50 articles (this reviewer has verified this today using SCOPUS), including high-ranking publications in Nature Chemistry, such as the work by Rahim et al. in Nature Chemistry, Volume 14, 935-941 from 2022. (DOI: 10.1038/s41557-022-00965-6).\nEven the idea to immobilize liquid Ga-Pt alloy droplets on porous supports for alkane dehydrogenation reactions is far from new. Under the name ‘Supported Catalytically Active Liquid Metal Solutions (SCALMS)’ (Nature Chemistry, 2017, 9(9), 862-867, DOI: 10.1038/nchem.2822, and paper citing this work) more than 30 paper have been published describing exactly this concept, 11 of these deal with Ga-Pt systems including preparation by ultrasonication and theoretical calculations to prove the isolated nature of Pt in Ga. Seven of these papers deal with propane dehydrogenation which is a very similar reaction to ethane hydrogenation.\nIn this light, this reviewer finds it striking that none of these earlier works were cited by Ziyue Zeng and coworkers. This is strange – and even if one takes into account the slightly different terminology used in the various articles – a proper and rigorous approach could have led to the conclusion that the work described in the current submission lacks the required novelty for a publication in Nature Communications.\nIn conclusion, this reviewer recommends studying the existing literature much more carefully and then publishing some of the interesting detailed information in the submitted manuscript in a much more specialised journal.", "reviewer_2": "In the manuscript, the authors described a strategy to realize the highly thermal-stable single-atom catalysts (SACs) resistance to sintering through harnessing the inherent metal affinity and fluidity of liquid metal. This work provides a novel approach for addressing the thermal instability of SACs under high-temperature conditions, which is regarded as the most critical and persistent challenge in single-atom catalysis. The proposed liquid metal-dispersed SACs exhibited outstanding thermal durability for ethane dehydrogenation, sustaining stable operation for over 100 h at 650 oC with an impressive ethylene selectivity of 98%. This work not only resolves a key limitation in SACs but also paves the avenue to practical deployment of SACs for practical industrial thermocatalysis.\nHence, I would like to recommend the publication in Nature Communications. The following are several minor details for the authors to consider:\n1. It is very interesting to use liquid metal with dynamic fluidity and metallicity to stabilize the single atoms. How can a single atom be \"anchored\" on this dynamically renewed surface? Is this anchoring a static \"locking\" or a dynamic \"stabilization\" that relies on the rapid dynamic reconfiguration of the liquid metal surface? I'd be very glad to hear some explanations or assumptions.\n2. As demonstrated in page 8 line 6, the Pt−Pt bond length is 2.65~2.79 Å. However, in Figure 2d, the authors drew a gray area between 2.65~3.35 Å. Does the grey area represent the inherent bond length of Pt−Pt, or is there any specific basis or standard for this range?\n3. In Figure 2f, the potential energy of Pt–Pt (107.9 kcal/mol) is lower than that of Ga–Pt and Ga–Ga. I wonder whether this is in contradiction to the opinion that Pt tends to form Ga–Pt bonds within liquid metal.\n4. Pt is regarded as a good catalyst for ethane dehydrogenation. I am very curious whether Ga and porous MFI zeolite (ZSM-5) will have any impact on the conversion and selectivity of the ethane dehydrogenation reaction. Ga/ZSM-5 was also proposed effective for dehydrogenation of alkanes(eg. DOI:10.1016/j.jcat.2024.115834; 10.1021/acscatal.7b04295, etc.). It would be better for the authors to elaborate on the catalytic performances of Pt/ZSM-5 and Pt@Ga/ZSM-5.\n5. The authors have demonstrated the unique advantages of liquid metal in dispersing single atoms and maintaining their high-temperature stability. I am curious whether liquid metal has any advantages over the solid carriers for synthesizing SACs. Please give corresponding explanations.\n6. A few specific minor errors:\n1) Redefining abbreviations: The authors have already defined the single-atom catalysts and given the abbreviation in line 2 of the abstract, but it is abbreviated again in line 5.\n2) Spelling mistake: in Supplementary Fig. 1, the word “luctuates” may be misspelled.\n3) Other error: in Supplementary Fig. 11, the x-coordinate is incorrect.", "reviewer_3": "This work reports liquid metal dispersed single-atom catalyst by dissolving Pt into molten Ga. In fact, it is the Pt-Ga nanoalloy in previous work. I cannot make sure this kind of nanoalloy with dissolving Pt into molten Ga is the single-atom catalyst. I donot agree with the definition of molten nanoalloy as liquid metal dispersed single-atom catalyst. Thus, I donot think this work should be published in Nature Communications. Other Comments:\n1) I suggest the authors to make sure the definition of single-atom catalyst. This kind of molten Pt-Ga nanoalloy is not new, and their catalytic mechanism is the contribution of both Pt and Ga. It is NOT the case of single-atom catalyst.\n2) The mechanism of high temperature stability is not clear. The authors need to prepare a single Pt atom in molten Ga, and Pt almost remain the top of the molten Ga cluster and also high temperature stability.\n3) The data analysis for liquid metal dispersed single-atom catalyst is not enough for understanding high temperature stability. How to certify that the Pt atoms donot form dimer and trimer inside the molten Ga after long-time high temperature test?"}, "author_response": "Reply to the referees\nTo Referee #1\nFirst of all, we really appreciate your constructive comments, which significantly\npromote the improvement of our work. According to your suggestions, we have made\ncorresponding revisions to our manuscript as listed below.\nOverall remark: The work by Ziyue Zeng's and coworkers deals with a very relevant\ntopic in the field of catalysis. The paper is well written and contains relevant information.\nHowever, the paper is not suitable for Nature Communications and needs to be\nfundamentally revised in order to be suitable for a more specialised journal in the future.\nThe reason is simple: the main claims of the article, namely that a single Pt atom can be\nstabilised in liquid gallium to perform high-temperature dehydrogenation catalysis in the\nform of supported liquid metal catalysis, are by no means new, but have already been\npublished (with slightly different terminology) in more than 50 articles (this reviewer has\nverified this today using SCOPUS), including high-ranking publications in Nature\nChemistry, such as the work by Rahim et al. in Nature Chemistry, Volume 14, 935-941 from\n2022. (DOI: 10.1038/s41557-022-00965-6).\nEven the idea to immobilize liquid Ga-Pt alloy droplets on porous supports for alkane\ndehydrogenation reactions is far from new. Under the name ‘Supported Catalytically Active\nLiquid Metal Solutions (SCALMS)’ (Nature Chemistry, 2017, 9(9), 862-867, DOI:\n10.1038/nchem.2822, and paper citing this work) more than 30 paper have been published\ndescribing exactly this concept, 11 of these deal with Ga-Pt systems including preparation\nby ultrasonication and theoretical calculations to prove the isolated nature of Pt in Ga.\nSeven of these papers deal with propane dehydrogenation which is a very similar reaction\nto ethane hydrogenation.\nIn this light, this reviewer finds it striking that none of these earlier works were cited by\nZiyue Zeng and coworkers. This is strange – and even if one takes into account the slightly\ndifferent terminology used in the various articles – a proper and rigorous approach could\nhave led to the conclusion that the work described in the current submission lacks the\nrequired novelty for a publication in Nature Communications.\nIn conclusion, this reviewer recommends studying the existing literature much more\ncarefully and then publishing some of the interesting detailed information in the submitted\nmanuscript in a much more specialised journal.\nAuthor reply: Thanks for your comment. We have made a point-by-point response to\nyour comments and carefully revised the manuscript. For your reference, please find our\nrevisions marked in the red copy. We hope the newly revised manuscript can be more\nunderstandable and informative to meet the demand for publication in Nature\nCommunications.\n1) In terms of the query that a single Pt atom can be stabilized in liquid gallium, the\nreviewer considered that it has been reported. We would like to clarify.\nOur work focuses on the severe sintering limitation of SACs at high temperatures\nin industrial catalysis. By leveraging the fluidity and metal affinity of liquid metal, we\nrealized the ultra-stable SACs at 650 oC. It is worth noting that the high temperature\ncontributes to the dispersion of single atoms in our work rather than the agglomeration\nsintering phenomenon in reported works, which is of great significance for promoting the\nindustrial application of SACs. The significance of our work lays as follows:\ni) The realization of highly thermal-stable SACs for industrial catalysis. SACs have\nemerged as promising candidates to replace conventional industrial catalysts owing to their\nexceptional catalytic activity and atomic efficiency. The high surface energy of single atoms\nrenders them prone to migration and subsequent sintering during catalytic processes,\nespecially at high temperatures. Thus, it remains a formidable obstacle to developing\nnovel catalysts with high-temperature thermal stability. We realized the highly thermal-\nstable SACs resistance to sintering at harsh conditions through harnessing the inherent metal\naffinity and fluidity of liquid metal. We believe this is a crucial step forward in promoting\nthe application of SACs in high-temperature industrial catalysis.\nii）A brand-new strategy for achieving highly thermal-stable SACs resistance to\nsintering by liquid metals. The monodispersion of Pt in liquid metals rather than\nagglomeration at high temperatures is a thermodynamically favorable process, which is\nowing to the selective breaking and formation of chemical bonds profiting from the inherent\nmetal affinity of liquid metal. Combined with the fluidity of liquid metal, active metal atoms\ncan move but remain confined to the liquid metal as the metallic single-atom state at high\ntemperatures. We have provided robust evidence for clarifying the mechanism.\nRegarding the work by Rahim et al. in Nature Chemistry, Volume 14, 935–941 from\n2022 (DOI: 10.1038/s41557-022-00965-6), we acknowledge that this work did indeed\ndisperse ~0.0001 at% Pt in liquid metal and applied it to the reactions that are limited at\nroom temperature, including the oxidation of pyrogallol, the oxidation of 3,3’,5,5’-\ntetramethylbenzidine, the reduction of methylene blue, and the electrochemical oxidation\nof CH OH. However, this article (Nat. Chem. 2022, 14, 935) does not suggest that liquid\n3\nmetal carriers can solve the problem of agglomeration of single atoms under high-\ntemperature conditions.\nTherefore, the core innovation of work and the previously reported works are\nessentially different. We don’t think these two articles conflict.\n2) As for immobilizing liquid Ga–Pt alloy droplets on porous supports, it has no\nrelationship with the core innovation of our work. The focus in this work is to utilize\nliquid metal to address the bottleneck of agglomeration of SACs.\nFirstly, the adoption of porous support is to reveal the thermal-stability essence for\nthe SACs dispersed by liquid metals while eliminating the influence of mass transfer.\nPorous support is a commonly used strategy to enhance the mass transfer, as it guarantees a\nrelatively chemical inertness and the absence of mass-transfer restrictions because of the\nlarge pore size and rich pore structure (Nat. Chem. 2017, 9, 862). We have already clarified\nthis in our manuscript (Fig. R1).\nFig. R1 | Ethane dehydrogenation performance of pure ZSM-5 and Pt@Ga/ZSM-5.\nSecondly, in response to your doubts, we have conducted a comprehensive literature\nsearch via SCOPUS, retrieving studies on Ga–Pt alloys for alkane dehydrogenation and\nidentifying five studies that dispersed the alloy on porous supports. In all these works, the\nporous carrier served merely to enhance mass transfer, and the main focus of the research\nlies in the catalytic performance of the Ga–Pt alloy itself. The work (Nat. Chem. 2017, 9,\n862) highlighted by the reviewer is the first to introduce liquid metal into traditional\nsupported catalysts. It involves the synthesis of a Ga–Pd bimetallic alloy by dissolving Pd\nwithin Ga and loading the alloy on the porous glass. And the authors employed Ga–Pd alloy\nfor propane dehydrogenation, which manifested ~50% selectivity to butenes at 445 oC for\n25 h. Compared to this work, our work demonstrates superiority from both material design\nand catalytic performance perspectives. We realized highly stable SACs with uniformly\ncoordinated active centers that significantly enhance selectivity. When applied to high-\ntemperature ethane dehydrogenation, the catalyst maintains 98% selectivity at 650 oC\nfor 100 h, substantially outperforming the referenced work. Furthermore, we have\nprovided theoretical evidence and detailed structural characterization to explore the\nmechanism of the excellent thermal stability of the catalyst. And for large-scale industrial\ncatalysis, the high cost of Pt significantly constrains large-scale applications. While existing\nresearch attempts to reduce Pt usage through alloying with Ga, achieving a balance between\nplatinum dispersion and activity in ethane dehydrogenation remains challenging.\nFurthermore, alkane dehydrogenation involves multi-step reaction pathways (such as\ndehydrogenation, desorption, and re-adsorption), and competitive reactions such as\ndehydrogenation, hydrogenation, and cracking may simultaneously occur on the Pt catalyst\nsurface. Consequently, the synthesis of Pt-based catalysts with highly uniform coordination\nenvironments still presents significant challenges. In this regard, our work provides an atom-\neconomical solution for practical industrial catalysis.\n3) Regarding the reviewer’s comment about the omission of relevant references, we\nhave conducted a comprehensive literature search via SCOPUS as suggested. Our work\nfocuses on addressing the critical sintering challenges in SACs toward high-temperature\nindustrial catalysis. Consequently, the cited references predominantly described the current\nstate and development of the SACs in our previous manuscript. Following your valuable\nsuggestion, we have now incorporated additional references on liquid metal-based catalysis\nto make the background introduction more comprehensive. We remain confident that our\nwork demonstrates significant innovation compared to previous studies in the field.\nChanges: Thanks for your comment. We acknowledged the previous research on liquid\nmetals conducted by others and have included references to it in the text. For your reference,\nwe have added the corresponding references in our revised manuscript. Please find our\nrevisions marked in the red copy. Finally, we thank the reviewer’s suggestion to make our\nmanuscript more rigorous, and we hope these revisions make our manuscript more\nunderstandable and informative to readers. Please find our revisions marked in the red copy\nof the revised manuscript.\n862−867 (2017).\nsynthesis. Nat. Nanotech. 19, 306−310, (2023).\ndehydrogenation of light alkanes on metals and metal oxides. Chem. Rev. 114, 10613–10653 (2014).\nAngew. Chem. Int. Ed. 61, e202201453 (2022).\ndilute copper platinum alloys. J. Am. Chem. Soc. 147, 11789–11799 (2025).\nnanoparticles generated from single-sites. J. Am. Chem. Soc. 140, 11674–11679 (2018).\nsites. Nat. Commun. 16, 5696 (2025).\nTo Referee #2\nWe appreciate the referee’s positive evaluation of our manuscript. We have made a\npoint-by-point response to your comments and carefully revised the manuscript as you\nsuggested. For your reference, please find our revisions marked in red.\nOverall remark: In the manuscript, the authors described a strategy to realize the\nhighly thermal-stable single-atom catalysts (SACs) resistance to sintering through\nharnessing the inherent metal affinity and fluidity of liquid metal. This work provides a novel\napproach for addressing the thermal instability of SACs under high-temperature conditions,\nwhich is regarded as the most critical and persistent challenge in single-atom catalysis. The\nproposed liquid metal-dispersed SACs exhibited outstanding thermal durability for ethane\ndehydrogenation, sustaining stable operation for over 100 h at 650 oC with an impressive\nethylene selectivity of 98%. This work not only resolves a key limitation in SACs but also\npaves the avenue to practical deployment of SACs for practical industrial thermocatalysis.\nHence, I would like to recommend the publication in Nature Communications.\nAuthor reply: We appreciate your positive evaluation of our manuscript to be published\nin Nature Communications. We have made a point-by-point response to your comments and\ncarefully revised the manuscript as you suggested. For your reference, please find our\nrevisions marked in the red copy of our revised manuscript.\nComment 1: It is very interesting to use liquid metal with dynamic fluidity and\nmetallicity to stabilize the single atoms. How can a single atom be \"anchored\" on this\ndynamically renewed surface? Is this anchoring a static \"locking\" or a dynamic\n\"stabilization\" that relies on the rapid dynamic reconfiguration of the liquid metal surface?\nI'd be very glad to hear some explanations or assumptions.\nAuthor reply: Thank you for your valuable comment. The anchoring of single atoms\n(Pt) in liquid metals fundamentally relies on a dynamic equilibrium between fluidity and\nstability, achieved through the synergistic interplay of stable metal bonds and surface\nreconfiguration. Profiting from the superior metal affinity of Ga with Pt, Pt–Pt bonds are\nbroken at elevated temperatures, and subsequently the mobile Pt atoms are captured by Ga\nto form a stable Pt–Ga interaction, accomplishing the highly efficient dispersion of Pt single\natoms. The fluidity of liquid metal and the stable Pt–Ga interaction ensure that the Pt atoms\ncan remain dynamically scattered throughout the whole liquid metal dispersion system.\nTo further validate the stability mechanism of Pt single atoms dispersed in Ga, we\nconstructed a Ga₇₉Pt₁ slab model. AIMD simulations were conducted to investigate the\nmotion trajectory of a single Pt atom in molten Ga (analyzing its vertical distance to the\nsurface). Throughout the 10 ps simulation period, a single Pt atom migrates relatively freely\nwithin molten Ga, with a depth from the Ga surface ranging from 0 to 4.84 Å (Fig. R2).\nStatistical analysis indicates a surface exposure probability of 56.3% for the isolated Pt atom.\nFurthermore, considering the susceptibility of metallic Ga to oxidation state, even under\nreducing atmospheres (e.g., H₂) at 923 K, a thin Ga₂O₃ layer may persist. To eliminate the\ninfluence of Ga oxidation on Pt exposure, we also constructed a Ga₇₉Pt₁O₁₀ slab model\nincorporating a small number of oxygen atoms and performed a 10 ps AIMD simulation.\nThe simulation results demonstrate that limited oxygen atoms form Ga₂O₃ clusters with\nsurface Ga atoms. Under the influence of these Ga₂O₃ clusters at the molten Ga surface, the\nPt atom primarily remains within the surface and subsurface regions, exhibiting a depth\nrange of 0 to 2.97 Å (Fig. R2). Notably, the surface exposure probability of the single Pt\natom increases significantly to 81.3%. The single Pt atom in liquid metal migrates freely as\nGa₈Pt or Ga₉Pt clusters, retaining a finite probability of surface exposure. Crucially, the\npresence of Ga₂O₃ clusters at the molten Ga surface dramatically enhances the probability\nof single Pt atom surface exposure. This indicates that the Pt single atom can be stabilized\nto the molten Ga surface at 923 K over extended periods, thereby serving as active sites\nfor the catalytic activation of C₂H₆ molecules.\nFig. R2 | The calculated curve of the distance between a single Pt atom and the surface Ga layer as\na function of time. Here, surface Ga atoms are characterized as top-layer Ga atoms in each frame\nstructure whose coordination number is two less than the maximum coordination number, with the zero\npoint in the z-direction defined as the average of the maximum and minimum z-coordinates of these\nsurface Ga atoms. Furthermore, the z-coordinate threshold for identifying exposed Pt atoms is defined as\nthe vertical distance corresponding to the closest packing radius of Re atoms relative to this zero reference\npoint.\nTherefore, the anchoring of a single atom does not rely on static “rigid locking” but is a\ndynamic process.\nComment 2: As demonstrated in page 8 line 6, the Pt−Pt bond length is 2.65~2.79 Å. However, in Figure 2d, the authors drew a gray area between 2.65~3.35 Å. Does the grey\narea represent the inherent bond length of Pt−Pt, or is there any specific basis or standard\nfor this range?\nAuthor reply: Thank you for your kind reminding. The gray area is marked to display\nthe range of bond length fluctuation during bonding between two Pt atoms. Beyond this\nthreshold, the Pt−Pt bond is considered dissociated, with the atoms existing in a single-atom\nstate. The intrinsic bond length of Pt–Pt fluctuates between 2.65 and 2.79 Å (J. Am. Chem.\nSoc., 1978, 100, 2074−2079). And generally, when the distance between the two atoms is\nless than 1.2 times (2.79 Å×1.2=3.35 Å) of the sum of their Cambridge Structural Database\n(CSD) covalent radii, it can be considered that no chemical bond has been formed between\nthese two atoms and they can be regarded as independent of each other (J. Comput. Chem.,\n2011, 33, 580; J. Chem. Phys., 2024, 161, 082503). Thus, the gray area spanning from 2.65\nto 3.35 Å was considered to be the distance of the Pt–Pt bond. And we have clarified this\npoint in our revised manuscript in Figure 2 (Supplementary Information).\nComment 3: In Figure 2f, the potential energy of Pt–Pt (107.9 kcal/mol) is lower than\nthat of Ga–Pt and Ga–Ga. I wonder whether this is in contradiction to the opinion that Pt\ntends to form Ga–Pt bonds within liquid metal.\nAuthor reply: Thank you for your kind reminding. As you put forward, the potential\nenergy of Pt–Pt (107.9 kcal/mol) is lower than that of Ga–Pt (74.9 kcal/mol) and Ga–Ga\n(32.5 kcal/mol) (Fig. R3). However, the dispersion of Pt in liquid metal Ga involves two\nprocesses, including the breaking of the Pt–Pt bond and the Ga–Ga bond, and the formation\nof two Ga–Pt bonds (149.8 kcal/mol). This is an exothermic process (9.4 kcal/mol).\nMoreover, the Ga–Ga bond in liquid Ga is weaker than that in Ga₂ molecules. Therefore,\nthe breaking of Pt–Pt bonds to form Ga–Pt bonds is more favorable thermodynamically,\nwhich is consistent with the perspective that Pt readily forms Ga–Pt bonds in liquid metal\nGa. The energetic advantage accompanied by the good affinity between Ga and Pt enables\nGa atoms to disrupt Pt–Pt bonds to form stable Pt–Ga–Pt bridging units. We also provided\na detailed elaboration on this matter from the perspectives of thermodynamics and kinetics\nin the manuscript.\nFig. R3 | The calculated potential energy curves of three diatomic systems: Ga , GaPt, and Pt .\n2 2\nComment 4: Pt is regarded as a good catalyst for ethane dehydrogenation. I am very\ncurious whether Ga and porous MFI zeolite (ZSM-5) will have any impact on the conversion\nand selectivity of the ethane dehydrogenation reaction. Ga/ZSM-5 was also proposed\neffective for dehydrogenation of alkanes (eg. DOI:10.1016/j.jcat.2024.115834;\n10.1021/acscatal.7b04295, etc.). It would be better for the authors to elaborate on the\ncatalytic performances of Pt/ZSM-5 and Pt@Ga/ZSM-5.\nAuthor reply: Thank you for your kind reminding. In our work, Ga was adopted as the\ndispersion to achieve atomic dispersion of the active metal. This ensures a highly uniform\ncoordination environment of Pt atoms, which contributes to the selectivity and durability\nof the SACs. The introduction of zeolite is a commonly used strategy to enhance mass\ntransfer. The adoption of Porous MFI zeolite (ZSM-5) is to reveal the thermal-stability\nessence for the SACs dispersed by liquid metals while eliminating the influence of mass\ntransfer. We have supplemented the catalytic performance data of Pt/ZSM-5 and\nPt@Ga/ZSM-5 to clarify the roles of the liquid metal and ZSM-5, hoping to address your\nquestions.\n1) Ga facilitates the atomic dispersion of active metals, and the highly uniform and stable\ncoordination environment of active centers underpins the exceptional selectivity and\ndurability of the SACs. Pt is recognized as an effective catalyst for alkane dehydrogenation\n(Angew. Chem. Int. Ed. 2024, 63, e202409556). However, its catalytic activity varies\nsignificantly across different particle sizes with a varied coordination environment of each\nPt atom (ACS Catal. 2025, 15, 12420; ACS Catal. 2021, 11, 9279). When used directly in\nalkane dehydrogenation, this anisotropy promotes side reactions and reduces overall\nselectivity. By dispersing Pt as single atoms onto Ga, a highly uniform coordination\nenvironment is established, which ensures superior catalytic selectivity. Besides, the\ncatalytic performances of Pt/ZSM-5 and Pt@Ga/ZSM-5 were investigated to further\ndemonstrate the role of liquid metal in enhancing catalytic performance. As shown in Fig.\nR4, benefiting from the introduction of Ga, the reaction conversion of ethane is increased\nfrom 10% to 18%, while the selectivity of ethylene is improved from 82% to 98%.\nFig. R4 | Ethane dehydrogenation performance of Pt/ZSM-5 and Pt@Ga/ZSM-5.\n2) The molecular sieve itself exhibits negligible catalytic activity, with a selectivity of\nonly 85% (Fig. R5). Its incorporation is intended to enhance gas-catalyst contact and\nimprove mass transfer efficiency.\nFig. R5 | Ethane dehydrogenation performance of pure ZSM-5 and Pt@Ga/ZSM-5.\nComment 5: The authors have demonstrated the unique advantages of liquid metal in\ndispersing single atoms and maintaining their high-temperature stability. I am curious\nwhether liquid metal has any advantages over the solid carriers for synthesizing SACs.\nPlease give corresponding explanations.\nAuthor reply: Thank you for your constructive comment. The traditional synthesis\nstrategies of SACs mainly contain impregnation method (J. Am. Chem. Soc. 2025, 147,\n32729), mass-selected soft-landing method (ACS Nano 2020, 14, 13279), coprecipitation\nmethod (J. Am. Chem. Soc. 2025, 147, 18737), atomic layer deposition strategy (Nature\n2025, 640, 668), the host-guest strategy (Nat. Chem. 2020, 12, 764), photochemical\nsynthesis (Science 2016, 352, 797), etc. In most of these methods, metal precursors (such as\nmetal nitrates, metal chlorides, and metal acetylacetonates) are selected as the starting\nmaterials and subjected to heat treatment or light irradiation to deconstruct the original\nstructure (J. Am. Chem. Soc. 2022, 144, 18155). Traditional synthesis methods of SACs\nrequire intricate procedures, including impregnation, aging, multiple drying cycles,\ntemperature-controlled thermal treatment, and acid washing purification. These processes\nare not only lengthy but also involve multiple sensitive variables (e.g., pH, temperature,\nheating rate), posing significant challenges to reproducibility. Furthermore, these methods\nusually cannot be simply extrapolated to other systems due to their high dependence on\nmetal-support interactions.\nThe advantages of liquid metal for synthesizing SACs are as follows:\n1) The convenience and highly reproducible ability. The conventional synthesis\nstrategies necessitate precise sequential control over impregnation, drying, pyrolysis, and\nacid washing. In contrast, the liquid metal strategy requires only physical mixing of active\nmetal precursors (e.g., nanoparticles or even foils) with low-melting-point liquid metals\n(e.g., gallium, indium), followed by heating above the melting point under an inert\natmosphere. Active metals spontaneously dissolve and disperse into single atoms within the\nliquid metal dispersion, eliminating all intermediate processing steps.\n2) Excellent universality. Traditional synthesis approaches suffer inherent limitations\ndue to their reliance on metal-support interactions, which cannot be simply extrapolated to\nother systems. Typically, one approach is only applicable to specific metal-support\ncombinations (e.g., Pt on TiO₂, Fe on N-C), necessitating extensive screening efforts to\ndevelop new systems (Angew. Chem. Int. Ed. 2024, e202405017). However, since liquid\nmetals and most metals possess good affinity, our strategy exhibits near-universal\napplicability. And driven by thermodynamics (the negative mixing entropy), any target\nmetal can be dispersed as single atoms in the liquid metal.\n3) Near-100% atomic utilization efficiency for the active metal. Conventional\nsynthesis routes incur active metal loss during high-temperature precursor volatilization and\nacid-washing purification. In our method, the dissolution of active metal within the liquid\nmetal suppresses volatilization, while the synthesis itself constitutes a purification process,\nentirely eliminating acid-washing steps required to remove nanoparticles in traditional\nmethods. Consequently, virtually all introduced active metal atoms convert to utilizable\nsingle-atom sites.\n4) Highly uniform active site microenvironments enable precisely tunable catalytic\nperformance. On conventional solid supports (e.g., porous carbon, metal oxides),\nanchoring sites (vacancies, doped N atoms, surface hydroxyl groups) exhibit inherent\nheterogeneity in size, electronegativity, and spatial geometry. Therefore, the generated\nsingle-atom active sites do not have a single structure, and their catalytic activity and\nselectivity will be weakened, making it difficult to conduct precise structure-activity\nrelationship studies. Conversely, the homogeneous bulk environment of liquid metals\nensures a highly uniform coordination geometry for every active-metal atom, thereby\nguaranteeing high selectivity in subsequent catalytic processes. Liquid metal provides an\nideal platform for atomic-level catalytic design and modulation.\nComment 6: A few specific minor errors: 1) Redefining abbreviations: the authors have\nalready defined the single-atom catalysts and given the abbreviation in line 2 of the abstract,\nbut it is abbreviated again in line 5. 2) Spelling mistake: in Supplementary Fig. 1, the word\n“luctuates” may be misspelled. 3) Other error: in Supplementary Fig. 11, the x-coordinate\nis incorrect.\nAuthor reply: Thank you for your kind reminding. We have carefully examined the\nwhole manuscript and corrected the errors to make our manuscript more complete.\nChanges: In our revised manuscript, we have addressed all the issues raised by the\nreviewer, including repeated abbreviations, spelling mistakes, and incorrect axis numbers.\n1) Page 2: Unfortunately, SACs are fundamentally constrained by the stability owing to\nthe severe aggregation of single atoms, especially under the high-temperature\nthermocatalysis operations, which compromises the overall catalytic performance.\n2) The caption for Supplementary Fig. 1 on page 6: In the Ga Pt system, the shortest\n90 10\nPt–Pt distance fluctuates between 2.51 Å and 3.65 Å, which are partly in the range of 1.2\ntimes the length of the Pt–Pt bond (2.65 ~ 2.79 Å)5.\n3) Supplementary Fig. 11 on Page 16:\nSupplementary Fig. 11 | In situ XRD patterns of Pt@Ga on ZSM-5 in the process of heating up.\nInitially, the characteristic peaks of Pt can be apparently observed, which are located at 39.8o and 46.3o.\nWith the temperature increasing, the characteristic peaks of Pt were gradually weakened and disappeared\nsubsequently, proving the dispersion of Pt particles.\nFinally, we thank the reviewer’s suggestion to make our manuscript more rigorous, and\nwe hope these revisions make our manuscript more understandable and informative to\nreaders. Please find our revisions marked in the red copy of the revised manuscript.\nTo Referee #3\nFirst of all, we really appreciate your constructive comments, which significantly\npromote the improvement of our work. According to your suggestions, we have made\ncorresponding revisions to our manuscript as listed below.\nOverall remark: This work reports liquid metal dispersed single-atom catalyst by\ndissolving Pt into molten Ga. In fact, it is the Pt-Ga nanoalloy in previous work. I cannot\nmake sure this kind of nanoalloy with dissolving Pt into molten Ga is the single-atom\ncatalyst. I do not agree with the definition of molten nanoalloy as liquid metal dispersed\nsingle-atom catalyst. Thus, I do not think this work should be published in Nature\nCommunications.\nAuthor reply: Thank you for your kind reminding. The catalyst proposed in our\nmanuscript can be classified as a single-atom alloy (SAA) catalyst, which is a kind of SACs.\nTo clarify the rationale for categorizing our catalyst, we combined the definition of catalysts\nand their structural characteristics to illustrate. We have carefully checked the references to\nclarify the definitions of alloy, nanoalloy, single-atom catalysts (SACs), and single-atom\nalloys (SAAs). Besides, the experimental characterization evidence was also provided to\nassist in proving the single-atom state of Pt.\n1) Firstly, the catalyst proposed in our work conforms to the core definition of the\nsingle-atom alloy catalysts that fall within the category of SACs. We systematically\nanalyzed the fundamental distinctions between alloys, nanoalloys, SACs, and SAAs to\naddress reviewers’ concerns (Fig. R6). Alloy catalysts have a long history and have been\ndeveloping over nearly 100 years (J. Chem. Educ. 1929, 6, 2097). Building upon the\nclassical definition wherein alloys are most conveniently defined as a metallic system\ncontaining two or more components, irrespective of their intimacy of mixing or precise\nmanner of mixing (V. Ponec, G.C. Bond, Catalysis by Metals and Alloys, Elsevier,\nAmsrerdam, 1995; Applied Catalysis A: General 2001, 222, 31). When the size of the alloy\nis reduced to the nanoscale level, they are named “nanoalloys” and their properties are\ndistinctly different from the bulk or single metal counterparts (Adv. Mater. 2018, 30,\n1705698). Specifically, when dopant metal atoms are isolated completely by the host metal\natoms, the alloys are defined as the SAAs (Science 2012, 335, 1209; Phys. Chem. Chem.\nPhys. 2013, 15, 12187; Chem. Rev. 2023, 123, 5859). In addition, SAAs also constitute a\nsubset of SACs (Mater. Today Cataly. 2023, 2, 100009).\nFig. R6 | A summary of the definitions of alloy, nanoalloy, SAC and SAA.\n2) Secondly, the monodispersion state of Pt atoms within Ga has been confirmed\nby both X-ray absorption fine structure (XAFS) measurements and theoretical\nsimulations, which strictly complies with the core definition of SACs. XAFS results have\nclearly demonstrated that the Pt–Pt bond is absent and there exists the Ga–Pt bond in the\nliquid metal-based catalyst (Fig. R7), indicating that Pt atoms exist in the form of single\natoms. Meanwhile, through ab initio molecular dynamics (AIMD) simulations under high-\ntemperature conditions, it is shown that the average distance between Pt atoms and Ga atoms\nis much longer than the intrinsic bond length of Pt–Pt (2.65–2.79 Å) (Fig. R8), and no\nformation of Pt dimers or clusters has been detected in the dynamic statistics.\nFig. R7 | FT Pt L -edge EXAFS spectra in R space of liquid catalyst with phase correction.\n98 2\nsimulation.\nChanges: Thanks for your comment. We have acknowledged the previous research on\nliquid metals conducted by others and have included references to it in the text. For your\nreference, please find our revisions marked in the red copy. Once again, we apologize for\nour lack of rigor.\nComment 1: I suggest the authors to make sure the definition of single-atom catalyst.\nThis kind of molten Pt–Ga nanoalloy is not new, and their catalytic mechanism is the\ncontribution of both Pt and Ga. It is NOT the case of single-atom catalyst.\nAuthor reply: Thank you for your kind reminding. Based on the definition of SACs and\nsupported by our experimental results, our catalyst is the case of SACs.\n1) Firstly, the structure of Pt–Ga catalyst in our work conforms to the core\ndefinition of SACs. The concept of “SACs” was first proposed by Zhang, Li, Liu, and co-\nworkers in 2011 (Nat. Chem. 2011, 3, 634). The SACs, as defined originally, are “one kind\nof supported metal catalyst with isolated metal atom sites, where the core metal atoms in\nthe active sites are not closely connected but interact with support” (Acc. Chem. Res. 2025,\n58, 1878). In our manuscript, the experimental results all confirm the isolated nature of\nthe Pt atoms in our catalyst (Fig. R6 and Fig. R7), which is consistent with the core\ndefinition of SACs.\n2) Secondly, the catalytic performance of this Pt–Ga catalyst is mainly contributed\nby Pt atoms. SACs predominantly rely on monodispersed atomic sites as active centers,\nwhere the support primarily serves to anchor single atoms and modulates the electronic\nstates of isolated atoms through interfacial charge transfer effects. In our manuscript, liquid\nmetal not only disperses Pt single atoms, but its dynamic fluidity can also promote the\nmovement of single atoms. The activity of the catalyst mainly stems from the isolated Pt\nsingle-atom sites dispersed in Ga. The liquid metal was introduced to achieve atomic\ndispersion of the active metal, establishing a highly uniform coordination environment of\nPt to ensure superior catalytic selectivity. Meanwhile, the adoption of porous supports is\nmainly to enhance the gas mass transfer efficiency, which we have already clarified in our\nmanuscript. Porous supports are universally employed during catalytic processes, as they\nguarantee a relatively chemical inertness and the absence of mass-transfer restrictions\nbecause of the large pore size and rich pore structure (Nat. Chem. 2017, 9, 862). By\ncomparing the conversion and selectivity of pure ZSM-5, pure Ga, and Pt@Ga/ZSM-5,\nit is obvious that both ZSM-5 and Ga have no impact on the activity. The main catalytic active\ncenter is still Pt (Fig. R9).\nFig. R9 | Ethane dehydrogenation performance of liquid metal dispersed SACs. a The conversion\nof ethane. b The selectivity of ethylene.\nHence, the Pt single atoms dispersed by liquid Ga conform to the core definition of\nSACs (atomic-level dispersion, isolated active sites), can be considered a kind of dynamic\nSACs.\nChanges: Thanks for your comment. We have acknowledged the previous research on\nliquid metals conducted by others and have included references to it in the text. For your\nreference, please find our revisions marked in the red copy.\nComment 2: The mechanism of high temperature stability is not clear. The authors need\nto prepare a single Pt atom in molten Ga, and Pt almost remain the top of the molten Ga\ncluster and also high temperature stability.\nAuthor Reply: Thank you for your valuable suggestion. Following your suggestion, the\nstability mechanism of Pt single atom on Ga was demonstrated through the theoretical\ncalculations. We constructed the simulation model, in which the atom ratio and temperature\nare strictly consistent with those in the experiment. The results confirmed the single-atom\ndispersion state of Pt atoms in liquid metal, consistent with the experimental findings.\n1) Theoretical calculations have proved that a single Pt atom in molten Ga can\nfreely migrate in the molten Ga, and there is a certain probability for it being exposed\non the Ga surface. To validate this mechanism, we constructed a Ga₇₉Pt₁ slab model. AIMD\nsimulations were conducted to investigate the motion trajectory of a single Pt atom in molten\nGa (analyzing its vertical distance to the surface). Throughout the 10 ps simulation period,\na single Pt atom migrates relatively freely within molten Ga, with a depth from the Ga\nsurface ranging from 0 to 4.84 Å (Fig. R7). Statistical analysis indicates a surface exposure\nprobability of 56.3% for the isolated Pt atom. Furthermore, considering the susceptibility of\nmetallic Ga to oxidation state, even under reducing atmospheres (e.g., H₂) at 923 K, a thin\nGa₂O₃ layer may persist. To eliminate the influence of Ga oxidation on Pt exposure, we also\nconstructed a Ga₇₉Pt₁O₁₀ slab model incorporating a small number of oxygen atoms and\nperformed a 10 ps AIMD simulation. The simulation results demonstrate that limited\noxygen atoms form Ga₂O₃ clusters with surface Ga atoms. Under the influence of these\nGa₂O₃ clusters at the molten Ga surface, the Pt atom primarily remains within the surface\nand subsurface regions, exhibiting a depth range of 0 to 2.97 Å (Fig. R10). Notably, the\nsurface exposure probability of the single Pt atom increases significantly to 81.3%. The\nsingle Pt atom in liquid metal migrates freely as Ga₈Pt or Ga₉Pt clusters, retaining a finite\nprobability of surface exposure. Crucially, the presence of Ga₂O₃ clusters at the molten Ga\nsurface dramatically enhances the probability of single Pt atom surface exposure. This\nindicates that the Pt single atom can be stabilized to the molten Ga surface at 923 K\nover extended periods, thereby serving as active sites for the catalytic activation of\nC₂H₆ molecules.\nFig. R10 | The distance between a single Pt atom and the surface Ga layer. a The calculated curve of\nthe distance between a single Pt atom and the surface Ga layer as a function of time. b The illustration\nof the distance between a single Pt atom and the surface Ga layer. Here, surface Ga atoms are\ncharacterized as top-layer Ga atoms in each frame structure whose coordination number is two less than\nthe maximum coordination number, with the zero point in the z-direction defined as the average of the\nmaximum and minimum z-coordinates of these surface Ga atoms. Furthermore, the z-coordinate\nthreshold for identifying exposed Pt atoms is defined as the vertical distance corresponding to the closest\npacking radius of Re atoms relative to this zero reference point.\n2) The mechanism of high temperature stability stems from the stable interaction\nbetween Pt and Ga, which is validated by both thermodynamics and dynamics. Firstly,\nthermodynamic analysis reveals that the system exhibits a lower total energy for Pt\nmonodispersed in liquid metal than as clusters (Fig. R11a). Therefore, the remarkable\natomic diffusion of liquid Ga metal at high temperature promotes the migration of\nheterogeneous active metal atoms, thereby stabilizing their dispersed atomic state in liquid\nGa rather than forming dimers and trimers inside the molten Ga. Secondly, dynamic\nsimulations of Pt atoms diffusion within Ga demonstrate that Pt atoms are resistant to\naggregation. The Pt–Pt interatomic distance progressively increases from 4.18 Å to 11.63 Å\n(Fig. R11b), significantly exceeding the typical Pt–Pt bond length range of 2.65–2.79 Å (J.\nAm. Chem. Soc. 1978, 100, 2074). All these results confirm that Pt atoms maintain stable\nsingle-atom states under high temperature.\nFig. R11 | The thermodynamics and kinetics simulations of Pt atoms diffusion within Ga. a Total\nenergy versus time curves for the Ga\n10\nsystem containing clustered Pt\n10\nand dispersed Pt\n10\n. b Time\nevolution of Pt–Pt interatomic distance in the Ga Pt system under NVT ensemble simulation.\n98 2\n3) Stability evaluation of liquid metal dispersed SACs was evaluated in non-\noxidative ethane dehydrogenation at 923 K. It exhibits sustainable conversion and\nselectivity in the continuous reaction for 100 h, where the constant ethane conversion of\n~18% is obtained without attenuation (Fig. R12a). Furthermore, the EXAFS of liquid metal\ndispersed SACs after 100 h confirmed the preservation of atomically dispersed Pt within Ga\n(Fig. R12b, c). Hence, comprehensive stability evaluations combined with post-reaction\nstructural analysis reveal that Pt maintains atomic dispersion while participating in the\ncatalytic process.\nFig. R12 | Thermal stability performance of liquid metal dispersed SACs. a The long-term stability\ntest in ethane dehydrogenation. b XANES spectra of the liquid metal dispersed SACs after 100 h ethane\ndehydrogenation taken at Pt L edge. c k -weighted FFT spectra in R-space at Pt L edge.\n3 3 3\nComment 3: The data analysis for liquid metal dispersed single-atom catalyst is not\nenough for understanding high temperature stability. How to certify that the Pt atoms do\nnot form dimer and trimer inside the molten Ga after long-time high temperature test?\nAuthor reply: Thank you for your constructive comment. As you put forward, we have\nused both theoretical calculations and detailed experimental structural characterization to\nprove that the Pt atoms don’t form dimers or trimers inside the molten Ga after long-time\nhigh temperature test, hoping to resolve the reviewer’s doubt as much as possible.\n1) Thermodynamic analysis reveals that the system exhibits a lower total energy\nfor Pt monodispersed in liquid metal than as clusters. Using Pt as a model of Pt cluster,\n10\nwe investigated the structural evolution of both clustered and dispersed Pt in liquid Ga\n10\nduring 10 ps simulations at 923 K, in which the temperature is consistent with the reaction\ntemperature of ethane dehydrogenation in experiment. And calculated total energy versus\ntime curves for the Ga Pt system containing clustered Pt and dispersed Pt (Fig. R13).\n90 10 10 10\nThe dispersed Pt generally exhibits lower total energy compared to the aggregated Pt\n10 10\nclusters within the simulated 10 ps. The results indicate that the remarkable atomic diffusion\nof liquid Ga metal at high temperature promotes the migration of heterogeneous active metal\natoms, thereby stabilizing their dispersed atomic state in liquid Ga rather than forming\ndimers and trimers inside the molten Ga.\nFig. R13 | Theoretical calculations of heterogeneous active metal atoms monodispersed in liquid\nGa. a, b The extracted 0 ps, 5 ps, and 10 ps snapshots from AIMD trajectories of both clustered (a) and\ndispersed (b) Pt in liquid Ga. c Total energy versus time curves for the Ga Pt system containing\n10 90 10\nclustered Pt and dispersed Pt .\n10 10\n2) Dynamical simulations of Pt atoms diffusion within Ga demonstrate that Pt\natoms are resistant to aggregation. The actual existence state of Pt atoms in liquid Ga was\nstudied using AIMD simulations on the Ga Pt system (Pt dimer embedded in Ga ) at 923\n98 2 98\nK. The 10 ps NVT ensemble simulations (Fig. R14) demonstrate that the Pt–Pt interatomic\ndistance progressively increases from 4.18 Å to 11.63 Å, significantly exceeding the typical\nPt–Pt bond length range of 2.65–2.79 Å (J. Am. Chem. Soc. 1978, 100, 2074). These results\nconfirm that Pt atoms maintain stable single-atom states under high temperature.\nFig. R14 | Time evolution of Pt–Pt interatomic distance in the Ga Pt system under NVT ensemble\n98 2\nsimulation.\n3) The exact dispersion state of Pt in the Pt@Ga catalyst was further verified by X-\nray absorption spectroscopy (XAS) measurements. The k -weighted R-space Fourier\n3\ntransformed spectra of the extended X-ray absorption fine structure spectra (EXAFS) show\nthe prominent peak at 2.14 Å for Pt@Ga SACs, distinguished from that of the Pt–O (1.62\nÅ) bond for PtO and the Pt–Pt bond (2.24 Å) for Pt foil (Fig. R15a, b). Notably, the XANES\n2\nspectrum and R-space of liquid metal dispersed SACs after 100 h ethane dehydrogenation\nat Pt L -edge are similar to that of pristine liquid SACs (Fig. R15c, d), demonstrating\n3\nexceptional structural integrity under prolonged thermal catalysis. The absence of Pt–Pt\nbonds definitively confirms the exclusion of dimers or trimers.\nFig. R15 | Normalized XANES spectra at the Pt L\n3\n-edge and FT Pt L\n3\n-edge EXAFS spectra in R\nspace of liquid catalyst before and after the ethane dehydrogenation.\n4) The long-term stability test of liquid metal dispersed SACs further verified the\nstability of the atomically dispersed configuration. During the catalytic process, the state\nof the active center directly affects the catalytic pathway. Usually, the formation of Pt\nparticles leads to deep dehydrogenation of alkanes, resulting in a decrease in the selectivity\nand conversion of the catalyst. In our work, the performance of the liquid metal dispersed\nSACs in the durability test exhibits sustainable conversion and selectivity in the continuous\nreaction for 100 h, where the constant ethane conversion of ~18% is obtained without\nattenuation (Fig. R16). These results provide indirect evidence that the catalyst maintains a\nstable single-atom state.\nFig. R16 | Long-term stability test of liquid metal dispersed SACs.\nFinally, we want to thank the referees again for their constructive comments on our work,\nand we hope our revised manuscript can reach the quality expectation to be published in\nNature Communications. Please find our revisions marked in the red copy of the revised\nmanuscript."}, {"round": 2, "reviewer_comments": {"reviewer_2": "I read the manuscript carefully and found that the authors did a good job of revising it. The new version looks much better compared to the original one. As my concerns were fully addressed in this revision, I believe the manuscript is now publishable.", "reviewer_3": "I agree with Reviewer #1 that a single Pt atom can be stabilised in liquid gallium to perform high-temperature dehydrogenation catalysis is not new. The revision still lacks the required novelty for a publication in Nature Communications. I also agree with Reviewer #3 that the definition of molten nanoalloy is not liquid metal dispersed single-atom catalyst. This kind of molten Pt–Ga nanoalloy is not new, and should not be published in Nature Communications."}, "author_response": "Reply to the referees\nTo Referee #2\nFirst of all, we really appreciate your high evaluation to recommend our work to be\npublished in Nature Communications.\nOverall remark: I read the manuscript carefully and found that the authors did a\ngood job of revising it. The new version looks much better compared to the original one.\nAs my concerns were fully addressed in this revision, I believe the manuscript is now\npublishable.\nAuthor reply: Thank you very much for your positive feedback on our revised\nmanuscript. We are delighted to hear that you found the new version to be a significant\nimprovement and that your previous concerns have been fully addressed. We appreciate\nyour recommendation for publication.\nTo Referee #3\nWe have made a point-by-point response to your comments and carefully revised the\nmanuscript as you suggested. For your reference, please find our revisions marked in red.\nOverall remark: I agree with Reviewer #1 that a single Pt atom can be stabilised in\nliquid gallium to perform high-temperature dehydrogenation catalysis is not new. The\nrevision still lacks the required novelty for a publication in Nature Communications. I\nalso agree with Reviewer #3 that the definition of molten nanoalloy is not liquid metal\ndispersed single-atom catalyst. This kind of molten Pt–Ga nanoalloy is not new, and\nshould not be published in Nature Communications.\nAuthor reply: It is possible that the core innovation of our work may have been\ninadvertently understated. Our work focuses on the severe sintering limitation of single-\natom catalysts (SACs) at high temperatures in industrial catalysis. By leveraging the\nfluidity and metal affinity of liquid metal, we realized the ultra-stable SACs at 650\noC. Unlike the reported works that single atoms generally tend to aggregate at high\ntemperatures owing to Ostwald ripening or atom migration (J. Stat. Phys. 1985, 38, 231;\nAcc. Chem. Res. 2013, 46, 1720; Nat. Catal. 2021, 4, 469; Nat. Catal. 2025, 8, 1038), it\nis worth noting that the high temperature contributes to the dispersion single atoms\nprofited from the affinity between Ga and Pt in our work. Besides, the Pt–Ga catalyst\nin our work is exactly a kind of SACs. Regarding your question, we have made a point-\nby-point response, hoping to clear up your doubts.\n1) As for the definition of molten nanoalloy is not liquid metal dispersed SAC,\nwe would like to clarify. The catalyst proposed in our work aligns with the established\ndefinition of single-atom alloy catalysts (SAAs), which is a kind of SACs. And this has\nbeen evidenced by both theoretical calculations and experiments.\nThe Pt–Ga catalyst in our work conforms to the core definition of SACs. The\nconcept of “SACs” was first proposed by Zhang, Li, Liu, and co-workers in 2011, in\nwhich isolated single atoms were anchored onto nano-crystallites (Nat. Chem. 2011, 3,\n634). Up to now, the SACs are universally regarded as “one kind of supported metal\ncatalyst with isolated metal atom sites, where the core metal atoms in the active sites are\nnot closely connected but interact with support” (Acc. Chem. Res. 2025, 58, 1878). The\nconcept of “SAAs” was first put forward in 2012 by Georgios Kyriakou et al. with two\nkey characteristics, which fall within the category of SACs (Science 2012, 335, 1209).\n“Two key characteristics of SAAs are (i) the more active of the two components is present\nin the surface of the host metal at very low concentrations [~0.01 monolayer (ML)] and\n(ii) atoms of the more active component are thermodynamically more stable when\nsurrounded by the host metal such that no dimers or trimers are present at low coverage.”\nCurrently, it is commonly accepted that SAAs are a class of single-site catalysts in which\nsmall amounts of isolated metal atoms are present in the surface layer of a metal host.\nTypically, they are comprised of single atoms of a catalytically active metal alloyed into\nthe surface of a less reactive host metal (Chem. Rev. 2020, 120, 12044). Based on these\ncriteria, we conducted a rigorous comparison between the catalyst in our work and the\ndefinition of SAAs, confirming that the catalyst in our work fully satisfies the\nrequirements: (a) The Pt atoms are presented as the single-atom state within Ga and\ndynamically migrate onto the surface to parcipate in the catalytic reaction (which\nwas proved theoretically and in experiment); and (b) the Pt atoms are mainly active\ncenters (which was evidenced by the experiments). The detailed analysis is as follows:\nFirstly, the single-atom state of Pt within liquid metal was demonstrated by\ntheoretical calculation, machine learning, and experiments.\ni) Thermodynamic analysis reveals that Pt is more likely to exhibit as the single-\natom dispersion state within Ga from the perspective of thermodynamics. The\ndispersed Pt atoms generally exhibit lower total energy compared to the aggregated Pt\nclusters within the simulated 10 ps (Fig. R1).\nFig. R1 | Theoretical calculations of heterogeneous active metal atoms monodispersed in liquid\nGa. a, b The extracted 0 ps, 5 ps, and 10 ps snapshots from AIMD trajectories of both clustered (a)\nand dispersed (b) Pt in liquid Ga. c Total energy versus time curves for the Ga Pt system containing\n10 90 10\nclustered Pt and dispersed Pt .\n10 10\nii) Dynamical simulations of Pt atom diffusion within Ga demonstrate that Pt\natoms are resistant to aggregation. The actual existence state of Pt atoms in liquid Ga\nwas studied using AIMD simulations on the Ga Pt system (Pt dimer embedded in Ga )\n98 2 98\nat 923 K. The 10 ps NVT ensemble simulations (Fig. R2) demonstrate that the Pt–Pt\ninteratomic distance progressively increases from 4.18 Å to 11.63 Å, significantly\nexceeding the typical Pt–Pt bond length range of 2.65–2.79 Å (J. Am. Chem. Soc. 1978,\n100, 2074). These results confirm that Pt atoms maintain stable single-atom states under\nhigh temperature.\nFig. R2 | Time evolution of Pt–Pt interatomic distance in the Ga Pt system under NVT\n98 2\nensemble simulation.\niii) The statistical analysis dispersion state of Pt in the Pt–Ga catalyst.\nFurthermore, to more intuitively demonstrate the single-atom state of Pt atoms in Ga, we\ntrained a Ga–Pt neuroevolution potential model (which was updated in our revised\nmanuscript as Supplementary Fig. 9). Subsequently, we performed 20 ns NVT molecular\ndynamics simulations at 923 K on the Ga Pt and Ga Pt structures using the\n2063 43 21342 43\ntrained Ga–Pt machine-learning potential. The simulation results clearly indicate that the\nPt cluster rapidly disperses in liquid Ga (Fig. R3). Furthermore, we analyzed the\n43\nproportions of mono-dispersed and dimerized Pt states in all structures over the last 10 ns\n(Fig. R4). In the Ga Pt structure, the proportion of mono-dispersed Pt was 98.2%,\n2063 43\nwhile in the Ga Pt structure, it reached 99.9%. The results clearly demonstrate that\n21342 43\nin structures with Pt content of 2 at% or below, Pt atoms can be considered fully mono-\ndispersed at 923 K. To explore the dispersion state of Pt in Ga, we expanded the\ncalculation system and analyzed the proportion of Pt in a single-atom state and the\nformation of Pt clusters in a larger model. Therefore, Pt atoms exist as single atoms and\ndo not undergo aggregation in the Pt–Ga catalyst.\nFig. R3 | The 20 ns NVT molecular dynamics simulations at 923 K on the Ga Pt and\n2063 43\nGa Pt structures using the trained Ga–Pt machine-learning potential. Structural snapshots\n21342 43\nat different time points are shown with the side (xz) view. Dark blue and dark red spheres represent\nGa and Pt atoms, respectively, and to better illustrate the single-atom state of Pt atoms, the size of Ga\natoms has been relatively reduced.\nFig. R4 | The calculated proportions of mono-dispersed and dimerized Pt states in Ga Pt and\n2063 43\nGa Pt structures. Mono-dispersed Pt is defined as Pt atoms surrounded exclusively by Ga atoms\n21342 43\nwithin a 3.2 Å range, while Dimerized Pt is defined as Pt atom that, within a 3.2 Å range, is surrounded\nby Ga atoms and exactly one additional Pt atom.\niv) The single-atom dispersed state of Pt atoms in the Pt–Ga catalyst was proved\nby X-ray absorption fine structure (XAFS). XAFS results have clearly demonstrated\nthat the Pt–Pt bond is absent and there only exists the Ga–Pt bond in the liquid metal-\nbased catalyst (Fig. R5), indicating that Pt atoms exist in the form of single atoms.\nFig. R5 | FT Pt L -edge EXAFS spectra in R space of liquid catalyst with phase correction.\nmonodispersed atomic sites as active centers, where the support primarily serves to\nanchor single atoms and modulates the electronic states of isolated atoms through\ninterfacial charge transfer effects. In our manuscript, liquid metal not only disperses Pt\nsingle atoms, but its dynamic fluidity can also promote the movement of single atoms.\nThe activity of the catalyst mainly stems from the isolated Pt single-atom sites\ndispersed in Ga. The liquid metal was introduced to achieve atomic dispersion of the\nactive metal, establishing a highly uniform coordination environment of Pt to ensure\nsuperior catalytic selectivity. Meanwhile, the adoption of porous supports is mainly to\nenhance the gas mass transfer efficiency, which we have already clarified in our\nmanuscript. Porous supports are universally employed during catalytic processes, as they\nguarantee a relatively chemical inertness and the absence of mass-transfer restrictions\nbecause of the large pore size and rich pore structure (Nat. Chem. 2017, 9, 862). By\ncomparing the conversion and selectivity of pure ZSM-5, pure Ga, and Pt@Ga/ZSM-5,\nit is obvious that both ZSM-5 and Ga have no impact on the activity. The main\ncatalytically active center is still Pt (Fig. R6).\nFig. R6 | Ethane dehydrogenation performance of liquid metal dispersed SACs. a The conversion\nof ethane. b The selectivity of ethylene.\nTherefore, the detailed structural characterization and theoretical calculation\nresults have both proved that this catalyst conforms to the core definition of SAAs–\na kind of SACs.\n2) In terms of the query that a single Pt atom can be stabilized in liquid Ga, the\nreviewer considered that it has been reported. We would like to clarify.\nOur work focuses on the severe sintering limitation of SACs at high\ntemperatures in industrial catalysis. By leveraging the fluidity and metal affinity of\nliquid metal, we realized the ultra-stable SACs at 650 oC. It is worth noting that the\nhigh temperature contributes to the dispersion of single atoms in our work rather than the\nagglomeration sintering phenomenon in reported works, which is of great significance for\npromoting the industrial application of SACs. The significance of our work lies as follows:\ni) The realization of highly thermal-stable SACs for industrial catalysis. SACs\nhave emerged as promising candidates to replace conventional industrial catalysts owing\nto their exceptional catalytic activity and atomic efficiency. The high surface energy of\nsingle atoms renders them prone to migration and subsequent sintering during catalytic\nprocesses, especially at high temperatures. Thus, it remains a formidable obstacle to\ndeveloping novel catalysts with high-temperature thermal stability. We realized the\nhighly thermal-stable SACs resistance to sintering at harsh conditions through harnessing\nthe inherent metal affinity and fluidity of liquid metal (Fig. R7). We believe this is a\ncrucial step forward in promoting the application of SACs in high-temperature industrial\ncatalysis.\nFig. R7 | Normalized XANES spectra at the Pt L -edge and FT Pt L -edge EXAFS spectra in R\n3 3\nspace of liquid catalyst before and after the ethane dehydrogenation.\nii) A brand-new strategy for achieving highly thermal-stable SACs resistance\nto sintering by liquid metals. The mono-dispersion of Pt in liquid metals rather than\nagglomeration at high temperatures is a thermodynamically favourable process, which is\nowing to the selective breaking and formation of chemical bonds profiting from the\ninherent metal affinity of liquid metal. Combined with the fluidity of liquid metal, active\nmetal atoms can move but remain confined to the liquid metal as the metallic single-atom\nstate at high temperatures. We have provided robust evidence for clarifying the\nmechanism (Figure 2 and Supplementary Mov. S1 and S2 in our revised manuscript).\nBesides, X-ray absorption fine structure (XAFS) analysis provides unequivocal proof to\nverify the single-atom state of Pt in Ga before and after the ethane dehydrogenation (Fig.\nR5).\nRegarding the doubts about the reported works, we have conducted a\ncomprehensive literature search, retrieving studies on liquid metal Ga and Pt for\ndehydrogenation catalysis. Previous reports focus on the catalytic performance of the Pt\nin liquid metal limited in low-temperature or the catalytic performance of the alloy state\nin thermal catalysis (Nat. Chem. 2022, 14, 935; ACS Appl. Nano Mater. 2024, 7, 24356;\nFuel, 2024, 369, 131788; ACS Catal. 2021, 11, 13423). It is finding that our work first\nproposed and confirmed that liquid metals can solve the problem of severe sintering of\nsingle atoms under extremely high-temperature conditions, which was not reported before.\nTherefore, the core innovation of work and the previously reported works are\nessentially different. We don't think these articles conflict.\nChanges: We have added the theoretical calculations to demonstrate the single-atom\nstate of Pt atoms within Ga more intuitively by training a Ga–Pt neuroevolution potential\nmodel in our revised manuscript. And we also verified that Pt can be stably dispersed on\nthe Ga surface to exert catalytic activity. The changes in the revised manuscript are\nmarked in red copy.\nPage 9 in the revised manuscript:\nTo more intuitively demonstrate the mono-dispersion state of Pt atoms in Ga, we\nconstructed Ga Pt and Ga Pt structures with Pt contents of 2 at% and 0.2 at%,\n2063 43 21342 43\nrespectively (Supplementary Fig. 8). Meanwhile, based on a training dataset containing\n17347 structures and a test dataset of 1926 structures, we trained a Ga–Pt neuroevolution\npotential model (Supplementary Fig. 9). Subsequently, we performed 20 ns NVT\nmolecular dynamics simulations at 923 K on the Ga Pt and Ga Pt structures\n2063 43 21342 43\nusing the trained Ga–Pt machine-learning potential. The simulation results clearly\nindicate that the Pt cluster rapidly disperse in liquid Ga (Supplementary Fig. 10).\nall structures over the last 10 ns (Fig. 2g). In the Ga Pt structure, the proportion of\n2063 43\nmono-dispersed Pt was 98.2%, while in the Ga Pt structure, it reached 99.9%. The\n21342 43\nresults clearly demonstrate that in structures with Pt content of 2 at% or below, Pt atoms\ncan be considered fully mono-dispersed at 923 K. Moreover, the calculated average\nnumbers of surface atoms in the Ga Pt and Ga Pt structures are 5.4 and 3.0,\n2063 43 21342 43\nrespectively (Supplementary Fig. 12 and Supplementary Fig. 13), and the temporal\nevolution of the vertical migration of individual Pt atoms and their probability distribution\ndemonstrate a preferential tendency to migrate toward the surface (Supplementary Fig.\n14). These indicate that a certain proportion of mono-dispersed Pt atoms can continuously\nexist on the liquid surface and participate in relevant catalytic reactions.\nPage 5–7 in the revised Supplementary Information:\nGa–Pt machine learning force field training and molecular dynamics simulations\nWe constructed a dataset for the Ga–Pt binary system, comprising 17347 training\nstructures and 1926 test structures. These structures cover bulk and surface structures of\nα-Ga, β-Ga, γ-Ga, Pt, Ga Pt, Ga Pt, Ga Pt , Ga Pt and Ga Pt , Ga–Pt bulk structures with\n2 3 3 2 3 5 7 3\nvarying compositions (Ga Pt , Ga Pt , Ga Pt , Ga Pt , Ga Pt , Ga Pt , Ga Pt ,\n50 1 49 2 48 3 47 4 46 5 45 6 44 7\nGa Pt , Ga Pt , Ga Pt , Ga Pt , Ga Pt , Ga Pt , Ga Pt , Ga Pt , Ga Pt ,\n43 8 42 9 41 10 40 11 39 12 38 13 37 14 36 15 35 16\nGa Pt , Ga Pt , Ga Pt , Ga Pt ). Nanoparticle systems such as Pt , Pt , Pt and\n34 17 33 18 32 19 31 20 6 13 19\nPt were also considered. The dataset was initially generated using isothermal–isobaric\n43\n(NPT) Ab initio molecular dynamics (MD) simulations under ambient pressure (0.0001\nGPa) and temperatures ranging from 0 to 9000 K. A machine learning potential was\ntrained using data from ab initio molecular dynamics (AIMD) simulations.\nDensity Functional Theory Calculations\nDensity functional theory (DFT) calculations were performed using the Vienna Ab initio\nsimulation package (VASP). The calculations employed a plane-wave basis set with the\nprojector augmented-wave (PAW) method and standard pseudo-potentials for Ga and Pt.\nThe GGA-PBE density functional was selected, along with D3 dispersion interaction\nsol\ncorrections. All calculations were conducted in high-precision mode (PREC = Accurate),\nwith a plane-wave cutoff energy set to 400 eV and without symmetry constraints (ISYM\n= 0). To ensure accuracy, the electronic self-consistent loop converged to a tolerance of\n10–6 eV (EDIFF=1.0E–6). The Methfessel-Paxton first-order smearing method\n(ISMEAR=1) was applied. The conjugate gradient algorithm was used for electronic\nminimization, and the maximum number of steps for electronic self-consistent (SCF)\ncycles was set to 999. A k-point mesh was automatically generated based on the reciprocal\nlattice vectors of the unit cell, with a k-point spacing of approximately 0.040 Å–1 in each\ndirection. Only single-point calculations were performed, as the DFT computations were\nprimarily used to generate labels for training data.\nMachine Learning Force Field Training\nThe training of the force field is performed using the efficient Neural Evolutionary\nPotential (NEP) method and the GPUMD code. The training dataset is sourced from the\npreviously completed PBE -D3 calculations. The cutoff radii for the radial and angular\nsol\ndescriptors are set to 8 Å and 6 Å, respectively. The weights for energy, force, and virial\nstress are 1.0, 1.0, and 0.1, respectively. The number of neurons in the hidden layer of the\nneural network (NN) is 50. The NEP potential function underwent 200000 optimization\niterations over the entire training set. The final results include the root mean square errors\n(RMSE) of energy and atomic forces.\nPage 10:\nSupplementary Fig. 4 | Statistical distribution of Pt coordination numbers in Ga Pt from\n98 2\nAIMD simulations. The coordination environment of Pt atoms in the Ga Pt system shows that\n98 2\nthe dominant coordination numbers for individual Pt atoms are 8 or 9, implying that mono-\ndispersed Pt atoms migrate within liquid Ga in the form of clusters such as Ga₈Pt or Ga₉Pt.\nPage 15~21:\nSupplementary Fig. 8 | The constructed Ga Pt and Ga Pt structures with Pt\n2063 43 21342 43\ncontents of 2 at% and 0.2 at%, respectively. In the subsequent catalytic process, to maximize\natom economy, a liquid metal-based catalyst with 0.2 at% Pt content was selected for catalytic\ntesting. Therefore, we also constructed a 0.2 at% Pt structure. Dark blue and dark red spheres\nrepresent Ga and Pt atoms, respectively, and to better illustrate the single-atom state of Pt atoms,\nthe size of Ga atoms has been relatively reduced.\nSupplementary Fig. 9 | The trained Ga–Pt neuroevolution potential model. a Sketch-map\nvisualization of the Ga–Pt structural dataset. b, c The regression plots for Ga-Pt NEP evaluated\non the training set, with an RMSE in energy (b) per atom and atomic force (c) of 19.9 meV atom–\n1 and 119 meV Å–1, respectively. A sketch-map comprises 17347 structures, with each colored\npoint representing an individual atomic configuration (structure). The positions of the points are\ndetermined by principal component analysis of structural learning descriptors, and their colors\ncorrespond to the energy of the respective structure. The diversity of the dataset is illustrated by\ndisplaying examples of atomic configurations from different regions of the sketch map. In the\ncrystal structures, dark blue and dark red spheres represent Ga and Pt atoms, respectively.\nSupplementary Fig. 10 | The constructed Ga₂₃₁₆Pt₁₁₅₇ structure and the calculated solubility\ncurve of Pt atoms in this structure at 923 K over time. After training, the Ga–Pt machine\nlearning force field (MLFF) was first used to calculate the solubility of Pt in the Ga₂₃₁₆Pt₁₁₅₇\nstructure. We performed a 5 ns NVT ensemble simulation of the Ga₂₃₁₆Pt₁₁₅₇ structure at 923 K\nwith a time step of 2 fs. For the solubility evaluation, the ratio of the number of Ga atoms with\nonly Ga atoms as nearest neighbors within a 3.2 Å range to the total number of Ga atoms was\nstatistically analyzed. The calculated average solubility of Pt in liquid Ga at 923 K was 13.6%,\nwhich is consistent with experimental results8. This demonstrates that the constructed machine\nlearning force field can effectively evaluate the dissolution properties of Pt in Ga.\nSupplementary Fig. 11 | The 20 ns NVT molecular dynamics simulations at 923 K on the\nGa Pt and Ga Pt structures using the trained Ga–Pt machine-learning potential.\n2063 43 21342 43\nStructural snapshots at different time points are shown with the side (xz) view. Dark blue and dark\nred spheres represent Ga and Pt atoms, respectively, and to better illustrate the single-atom state\nof Pt atoms, the size of Ga atoms has been relatively reduced.\nSupplementary Fig. 12 | Statistical distribution of coordination numbers for Pt atoms in\nGa₂₀₆₃Pt₄₃ from molecular dynamics simulations. Pt atoms with coordination numbers of 6 or\nbelow are considered surface Pt atoms. Calibrating the vertical height range of surface atoms\nbased on the number of surface atoms obtained from the difference in coordination numbers.\nSupplementary Fig. 13 | The curves of the number of surface atoms over time in the\nGa₂₀₆₃Pt₄₃ and Ga₂₁₃₄₂Pt₄₃ structures, where the surface atom region is defined as (Zₘₐₓ – 4.5)\nto Zₘₐₓ and Zₘᵢₙ to Zₘᵢₙ + 4.5. The 4.5 Å threshold is determined based on the equivalence\nbetween the number of atoms counted in these regions and the number of atoms counted with a\ncoordination number less than or equal to (the most frequent coordination number – 2)\n(Supplementary Fig. 12).\nSupplementary Fig. 14 | The temporal evolution of the vertical migration for three randomly\nselected Pt atoms, and the probability density distribution of one of these Pt atoms along the\nvertical direction."}, {"round": 3, "reviewer_comments": {"reviewer_4": "The authors have responded to all the reviewers' comments appropriately.", "reviewer_5": "The authors have satisfactorily addressed all of my previous concerns. I recommend accepting the manuscript in its present form."}, "author_response": "Reply to the referees\nTo Referee #4\nFirst of all, thank you very much for your evaluation of our work. According to your suggestion,\nwe have supplemented a point-to-point reply with systematic experiments and discussions. We hope\nthat our revised manuscript is considered to be published in Nature Communications.\nOverall remark: In the manuscript entitled “Liquid metal dispersed single-atom catalyst with\nhigh-temperature stability” submitted to Nat. Commun., Zeng et al. report a Pt-based single-atom\ncatalyst dispersed in a Ga-based molten phase and supported on ZSM-5 for ethane dehydrogenation\nto ethylene. The authors imply that this constitutes a new conceptual way of stabilizing SACs with\nhigh activity and thermal stability, and they support their arguments by a combination of experimental\ndata and AIMD calculations.\nAuthor reply: Thanks a lot for your evaluation that “this constitutes a new conceptual way of\nstabilizing SACs with high activity and thermal stability, and they support their arguments by a\ncombination of experimental data and AIMD calculations.” Regarding the following detailed\nquestions that you put forward, we have supplemented systematic experiments and discussions,\nincluding the core innovation of our work, the generalizability of our findings, reaction kinetic\nanalysis, the long-term stability, deactivation pathways, and structure-performance relationships. We\nbelieve that the novelty, generalizability, and depth of our work have been greatly improved by your\ninsightful suggestion.\nComment 1: My main concern is that the central experimental claim about the unique role of Pt\nis not convincingly supported by the data as described. The authors state in their rebuttal letter that,\nupon “comparing the conversion and selectivity of pure ZSM-5, pure Ga, and Pt@Ga/ZSM-5,\nit is obvious that both ZSM-5 and Ga have no impact on the activity.” This is difficult to\nreconcile with the reported performance: Ga metal alone reaches approximately half the conversion of the Pt–Ga\nsingle-atom system and even exhibits higher selectivity to ethylene. These numbers strongly suggest\nthat Ga is an active and selective catalyst on its own and that the incremental contribution of Pt to\nthe overall performance is limited. Rather than demonstrating a clear, dominant role of Pt single\natoms in a molten Ga host, the data point to a system in which Ga already performs well and Pt\nprovides a modest, enhancement in conversion at (perhaps) the cost of selectivity. The authors need\nto acknowledge and analyze this more carefully; in its current form, the narrative that Ga and ZSM-\n5 “have no impact on the activity” is not credible.\nAuthor reply: Thank you very much for your constructive feedback on our revised manuscript.\nRegarding your questions about the contribution of Ga, and Pt to the overall ethane dehydrogenation\n(EDH) performance, we conducted supplementary experiments. The results indicate that Ga and\nZSM-5 do not provide additional catalytically active sites for EDH. Ga mainly serves as a dispersion\ncarrier, enabling high catalytic activity by dispersing metal Pt particles into single atoms. And the\nZSM-5 was used to enhance the gas mass transfer. The detailed analysis is listed below:\n(1) Regarding whether Ga or ZSM-5 is an active and selective catalyst on its own, we\nsupplemented experiments with blank U-tubes. Due to the fluidity of liquid metal Ga, conventional\nU-tubes cannot meet the requirements for EDH testing. In this work, we customized a home-made\nU-tube equipped with a quartz sieve plate to support the catalyst as well as to enhance the mass\ntransfer (Fig. R1). Under identical catalytic conditions, the catalytic performance of the blank U-tube\nand pure Ga (pure Ga@U-tube) is shown in Fig. R2. The ethane conversion and ethylene selectivity\nof the U-tube are derived from the thermal cracking reaction of ethane. Comparison of catalytic\nperformance reveals that the ethane conversion of pure Ga, and the blank U-tube remains essentially\nconsistent, suggesting that Ga does not provide additional catalytically active sites. Regarding the\nactivity ZSM-5, the ZSM-5 (Si/Al = 45) used in our work is usually considered to exhibit negligible\nactivity for ethane dehydrogenation to ethylene, and substantial catalytic performance is typically\nachieved through constructing tailored active sites via the surface immobilization of metal\nnanoparticles (ACS Catal. 2021, 11, 9970) or the encapsulation of clusters or isolated metal sites\nwithin its framework (Appl. Surf. Sci. 2021, 554, 149611; Chem 2023, 9, 637).\nFig. R1 | Schematic diagram of a quartz tube with a quartz sieve plate. The porous quartz sieve plate is\ndesigned to prevent liquid metal leakage.\nFig. R2 | Comparison of catalytic performance of blank U-tube, and pure Ga. (a) Conversion of ethane.\n(b) Selectivity of ethylene.\n(2) Ga mainly acts as a dispersion support to enable the monodispersed state of Pt atoms,\nwhich enhances the ethane conversion and ethylene selectivity. To further demonstrate the role of\nGa, we compared the catalytic performance of Pt particles@ZSM-5 (direct mixing of commercialized\nPt particles with ZSM-5 without utilizing Ga as dispersion) with that of Pt SACs@Ga/ZSM-5. Pt\nparticles@ZSM-5 exhibited ethane conversion at 9.5% and ethylene selectivity at 82.6% (Fig. R3).\nIn contrast, the Pt SACs@Ga/ZSM-5 catalyst, where Pt dissolves as single atoms within liquid Ga,\nachieves a significantly higher ethane conversion (17.8%) while maintaining excellent ethylene\nselectivity (98.3%). The breakthrough in performance stems from the introduction of liquid metal,\nwhich directly alters the dispersed state of Pt atoms (Fig. 2e, f in the revised manuscript). By\ndispersing Pt particles into single Pt atoms, the utilization of Pt atoms was maximized to achieve high\nethane conversion. Furthermore, the coordination environment of active metals significantly\ninfluences the reaction selectivity. Usually, Pt particles with a non-uniform coordination environment\ntypically promote C−C cleavage and deep dehydrogenation side reactions (ACS Catal. 2020, 10,\n12932). In contrast, Pt-based SACs with a uniform coordination environment exhibit excellent\nselectivity for ethylene due to their superior activation of C−H bonds in alkanes, while simultaneously\nlimiting C−C bond cleavage to prevent dehydrogenation reactions. Therefore, the introduction of\nliquid metal, which stabilizes Pt in a single-atom state with a highly uniform coordination\nenvironment, allows the Pt SACs@Ga/ZSM-5 catalyst to reach an ethylene selectivity of 98.3%.\nTaken together with the evidence that metallic Ga is catalytically inert (Fig. R2), we conclude that Ga\nacts as a liquid dispersion to scatter and stabilize Pt atoms.\nFig. R3 | Comparison of catalytic performance with and without the introduction of liquid metal. a\nConversion of ethane. b Selectivity of ethylene.\nChanges: To more clearly demonstrate the performance improvements achieved by dispersing Pt\nin liquid metal Ga, we replaced the performance comparison of pure Ga, pure ZSM-5, and Pt\nSACs@Ga/ZSM-5 catalysts in Fig. 4b, c with the catalytic performance of Pt particles@ZSM-5 and\nPt SACs@Ga/ZSM-5 catalysts. We also provided revised descriptions and analyses for the data in\nthe revised manuscript. The changes are marked in red.\nPage 14 in the revised manuscript:\nThe Pt particles@ZSM-5 catalyst, which is prepared by direct mixing of commercial Pt particles\nwith ZSM-5, exhibits ethane conversion at 9.5% and ethylene selectivity at 82.6% (Figs. 4b, c).\nInterestingly, the liquid metal dispersed SACs are highly active with ethane conversion at 17.8% and\nethylene selectivity at 98.3%. The breakthrough in performance stems from the introduction of liquid\nmetal, which directly alters the state of Pt. By dispersing bulk Pt into single Pt atoms, the utilization\nof Pt atoms is maximized to achieve high conversion rates. Furthermore, since the size of Pt particles\nsignificantly influences catalytic performance, larger Pt nanoparticles typically promote C−C\ncleavage and deep dehydrogenation side reactions37. In contrast, Pt-based catalysts dispersed at the\natomic scale exhibit excellent selectivity for ethylene due to their superior activation of C−H bonds\nin alkanes, while simultaneously limiting C−C bond cleavage to prevent dehydrogenation reactions.\nTherefore, when liquid metal is introduced, Pt exists in a single-atom state, enabling the Pt\nSACs@Ga/ZSM-5 catalyst to achieve nearly 100% selectivity.\nFig. 4 | Ethane dehydrogenation performance of liquid metal dispersed SACs. (a) Schematic showing the\nstructure evolution of adaptive surface active sites in liquid metal dispersed SACs when exposed to ethane\natmosphere. (b, c) Catalytic performances at 650 °C. (d) Long-term stability test. (e) XANES spectra of the\nliquid metal dispersed SACs after 100 h ethane dehydrogenation taken at Pt L edge. (f) k -weighted FFT\n3 3\nspectra in R-space at Pt L edge.\nliterature on SCALMS (Supported Catalytically Active Liquid Metal Solutions) and single-atom/alloy\ncatalysts. Ga–Pt and related molten metal/solid alloy catalysts have been studied for some time, in\nparticular by Peter Wasserscheid and co-workers and others, who have explicitly discussed high-\ntemperature stability and among others Ga-based systems. There are already reports that can\nreasonably be described as “single atom” or “single site” catalysts embedded in a liquid Ga host on\na support, including recent work (e.g. doi:10.1002/cphc.202400651) that addresses exactly the\nstability and site isolation arguments the authors here put forward. Against this background, the\nassertion that this manuscript is the first to propose the concept of a supported single-atom catalyst\nin a molten metal host appears overstated. The results read as an incremental variation within the\nestablished SCALMS/SAA/SAC framework rather than as a fundamentally new conceptual advance.\nAuthor reply: Thank you very much for your feedback on our revised manuscript. In terms of\nthe difference in our work and the reported SCALMS, especially the reference (doi:\n10.1002/cphc.202400651), we have conducted a comprehensive literature search via SCOPUS. We\nacknowledged that Prof. Peter and his colleagues, as well as others, have conducted important\nresearch in this field. However, the core innovation of our work is different from that of the reported\nworks.\nOur work focuses on the severe sintering limitation of SACs at high temperatures in\nindustrial catalysis. By leveraging the fluidity and metal affinity of liquid metal, we realized the\nultra-stable SACs at 650 oC for 100 hours. It is worth noting that the high temperature contributes\nto the dispersion of single atoms in our work rather than the agglomeration sintering phenomenon in\nreported works, which is owing to the selective breaking and formation of chemical bonds profiting\nfrom the inherent metal affinity of liquid metal. Combined with the fluidity of liquid metal,\nactive metal atoms can move but remain confined to the liquid metal as a single-atom state at high\ntemperatures. This finding is of great significance for promoting the industrial application of SACs.\nAnd we provided robust evidence through a combination of theoretical calculations and\nexperimental data (Fig. 2, Fig. 4 and Supplementary Movs. 1, 2 in the revised manuscript).\nAdditionally, immobilizing Ga–Pt on porous ZSM-5 is mainly to enhance the gas mass transfer\nefficiency. The focus in this work is to utilize liquid metal to address the bottleneck of agglomeration\nof SACs.\nWhile the reference (doi:10.1002/cphc.202400651) focuses on the Ga–Ni system within\nSCALMS for selective polymerization of ethylene. The active center of the catalyst is jointly\nformed by isolated Ni single atoms and Ga–Ni intermetallic compounds (e.g., Ga Ni, Ga₇Ni₃),\n5\nwhich is different from the isolated single atoms as active centers in our work. However, at elevated\ntemperatures, the low-melting-point Ga₅Ni undergoes a phase transformation into the high-\nmelting-point Ga₇Ni₃ intermetallic compounds (Fig. R4a). Due to the insolubility Ga₇Ni₃, Ga₇Ni₃\ncannot replenish Ni single atoms on the catalyst surface (Fig. R4b), leading to gradual depletion of\nactive sites and subsequent deterioration of catalyst stability (Fig. R4c). Therefore, the core\ninnovation, the stability of the catalyst, and structure-performance relationship of the reference\nare totally different from our work.\nFig. R4 | Deactivation Mechanism of Ga–Ni SCALMS. a Snapshots of in situ SAED at 298 K, 553 K and\ntemperatures ranging from 473 to 623 K.\nFurthermore, the synthetic approaches of our work and the reported SCALMS by Prof. Peter are\ndifferent. And the stability at high temperatures of our catalyst is outstanding among these\nreported works.\n1) A fundamental difference in the synthetic approaches. The approach of Prof. Peter\npredominantly relies on galvanic replacement driven by differences in reduction potential (Nat. Chem.\n2017, 9, 862) or impregnation-reduction (ChemCatChem, 2025, e202402096), whereby the salt of\nthe active metal reacts at the liquid Ga surface. However, galvanic replacement presents certain\nlimitations. One constraint is the uniformity of synthesis. The local electric field, ion concentration,\nand the distribution of reactants will result in differences in size, composition, distribution, or\nstructure of the active sites formed through galvanic replacement reactions. Another limitation is\nrestricted universality. Electrodeposition requires a potential difference between the two metals,\nmeaning only metals with lower electrode potentials can replace those with higher potentials.\nIn contrast, our work employs the direct dissolution of metallic Pt into liquid Ga. By\nleveraging the solvent properties of liquid metal and its strong affinity for Pt, we achieve stable Ga–\nPt interactions even at high temperatures, thereby efficiently forming highly uniform catalysts.\nThis highly uniform environment provides an efficient synthetic pathway for producing SACs with a\nhighly uniform coordination environment. Furthermore, Ga exhibits the favorable affinity and\nrelatively negative mixing enthalpy toward most metallic elements (Nature 2023, 619, 73), suggesting\nthe potential for universal synthesis of liquid metal dispersed SACs.\n2) The superior thermal stability of the catalyst in our work. By comparing the operating\ntemperatures and time on stream of catalysts in our work versus Prof. Peter’s (Tab. R1), it is found\nthat the catalysts in our work reveal a distinct advantage in thermal stability. In the reported work of\nProf. Peter that catalysts were synthesized by the galvanic replacement method, active metals are\ninitially enriched at the surface or interface. Besides, high-temperature calcination is typically\nrequired in this method to form the final SCALMS structure. At elevated temperatures, irreversible\ntransformations of the active sites lead to deactivation of the catalyst. Conversely, our catalyst\ncan maintain a stable single-atom state continuously without undergoing deactivation (evidenced by\nXAFS in Figs. 4 e, f and theoretical calculation in Fig. 2). This exceptional thermal stability stems\nfrom the stable interaction between Pt and Ga at high temperatures, which is a thermodynamically\ndriven process. This has been thoroughly evidenced at the atomic level from thermodynamic and\nkinetic perspectives in Fig. 2 in our revised manuscript.\nTab. R1 | Summary of Prof. Peter Wasserscheid’s work on SCALMS.\nType of Method of catalyst Tempera-ture Stability\nNo. Catalytic reaction Reference\ncatalyst synthesis (oC) (h)\nPropane ChemCatChem,\ndehydrogenation 2025, e202402096\nGa Pt/SiO Galvanic Propane ChemCatChem,\n2 46 2 600 15\nSCALMS displacement dehydrogenation 2025, e202500176\nGa-Ni Galvanic Ethylene ChemPhysChem,\n3 260 120\nSCALMS displacement oligomerization 2025, e202400651\nGalvanic Propane ACS Catal. 2025,\ndisplacement dehydrogenation 15, 12436\nACS Appl. Nano\nGalvanic Propane\ndisplacement dehydrogenation\n24356\nGa Pt/AlO Galvanic Dehydrogenation of n- React. Chem. Eng.\n6 84 2 3 430 8\nSCALMS displacement heptane 2024, 9, 1154\nGa-Ni Galvanic Dry reforming of Commun. Chem.\n7 900 20\nSCALMS displacement methane 2023, 6, 224\nGa-Pt, Ga-Pd,\nGalvanic Dehydrogenation of Chem. Eng. J 2023,\ndisplacement isobutane 475, 146081\nSCALMS\nGalvanic N-heptane Catal. Sci. Technol.\ndisplacement dehydrogenatio 2023, 13, 4435\nGa–Ni\nGalvanic Ethylene Catal. Sci. Technol.\ndisplacement oligomerization 2021, 11, 7535\n(Ga Ni/SiO)\n67 2\nGalvanic Propane ACS Catal. 2021,\ndisplacement dehydrogenation 11, 13423\nGa-Pd Galvanic Catalysts 2021, 11,\n12 / / /\ndisplacement 810\nGa–Pt Galvanic Propane Faraday Discuss.\n13 550 16.7\nSCALMS displacement dehydrogenation 2021, 229, 359\nGa Pt/SiO Galvanic Dehydrogenation of ChemCatChem\n14 52 2 450 75\nSCALMS displacement methylcyclohexane 2020, 12, 4533\nGa-Rh Galvanic Propane ChemCatChem\n15 500 6\nSACLMS displacement dehydrogenation 2020, 12, 1085\nGa-Rh Galvanic Propane ACS Catal. 2019, 9,\n16 550 15\nSACLMS displacement dehydrogenation 9499\nGa-Pd Galvanic Butane Nat. Chem. 2017, 9,\n17 445 25\nSACLMS displacement dehydrogenation 862\nTo further substantiate the thermal stability performance of our work, we also compared the\ncatalytic reaction temperatures and time on stream of our work with reported SACs (Tab. R2), where\nour results remain outstanding.\nTab. R2 | Comparison of thermal stability in this work and other SACs among reported works.\nTemperature\nCatalyst Reaction types Time (h) Reference\n(oC)\nPt SACs@Ga/ZSM-5 Ethane dehydrogenation 650 100 This work\nAppl. Catal. 2025, 366,\nCe-MoTiO Reduction of NO with NH 300 240\nx x 3 125021\nAngew. Chem. Int. Ed.\nRh/Fe-doped CeO Reduction of NO with CO 400 100\n1 2 2025, 64, e202421218\nNon-oxidative dehydrogenation of J. Mater. Chem. A 2022, 10,\nCo@MFI 650 40\nethane 9445\nIn/Rh@S-1 Propane dehydrogenation 600 5500 Science 2024, 383, 998\nJ. Energy Chem. 2024, 97,\nFe(II)-S-1 Ethane dehydrogenation 550 6\nChin. J. Catal. 2024, 57,\nNi/A-TiO Propane dehydrogenation 580 5\n2 105\nCatal. Commun. 2023, 176,\nGaPt/ZSM-5 Oxidative ethane dehydrogenation 650 3\n106631\nAngew. Chem. Int. Ed.\nNi/α-MoC Methanol dehydrogenation 240 100\n2025, e202423682\nAppl. Catal., B 2025, 365,\nPt/Ga Hydrogenation of acid to alkanes 255 6\nx 124915\nAdv. Mater. 2024, 36,\nNi-Mg SAA Mg hydrogen storage reaction 300 30 cycles\n1 2412942\nAppl. Catal., B 2024, 347,\nNi SAs/N-AlO Propane dehydrogenation 580 140\n2 3 123798\nAngew. Chem. Int. Ed.\nCu-FeO NH oxidation 300 100\n2 3 3 2024, 63, e202410457\nNatl. Sci. Rev. 2024, 11,\nMOF-808-NaCu CO hydrogenation to methanol 275 40\n2 nwae114\n110 h at 550 °C and Angew. Chem. Int. Ed.\nCo-Ba/YO Ammonia decomposition 500 – 600\n2 3 240 h at 500 °C 2025, 64, e202416195\nPt/CeO/SiO H reduction 300 10 Nature 2022, 611, 284\nx 2 2\nAppl. Catal., B 2025, 361,\nCu/γ-AlO Methane to methanol 200 12\n1 2 3 124648\nRu-(H)L(i-C)/AC Acetylene hydrochlorination 170 500 ACS Catal. 2025, 15, 3085\nRuNi SAA Hydrogenation of nitroarenes 60 3\nPdNi/SiO Hydrogenation of acetylene 80 12\n1 2 662, 119288\nSynthesis of piperidines and pyridine Nat. Commun. 2023, 14,\nRuCoNP 220 4\n1 from furfural 6329\nAngew. Chem. Int. Ed.\nRuNi SAA CO hydrogenation 400 140\n2 2025, 64, e202412835\nAppl. Catal., B 2022, 314,\nNi/CoCeO Dry reforming of methane 800 150\n1 2 121516.\nAcceptorless dehydrogenative\nCo/VO 359 0.5 Small 2023, 19, 2207941\n1 2 5 coupling of benzyl alcohol\nPt-NiCe@SiO Dry reforming of methane 550 120 ACS Catal. 2021, 11, 8247\nMn/V/AlO and Mn/Ni/ZrO 300 – 500 25 ACS Catal. 2024, 14, 16698\n2 3 2 propane\nNat. Commun. 2023, 14,\nFe-ZIF-8-800 Hydrogenation of furfural 60 – 120 6\nRh/SnO Ethylene hydroformylation 150 85\n1 2 2023, 62, e202214048\nHydrodeoxygenation of lignin to Chem. Eng. J 2025, 505,\nMo/NiFe -V 240 3\n71 naphthene 159303\nNi-SAs/N-CNTs Reverse water-gas shift reaction 500 100 ACS Catal. 2023, 13, 7132\nJ. Am. Chem. Soc. 2024,\nCo@Mo-S-1 Propane dehydrogenation 600 72\n146, 8939\nChin. J. Catal. 2023, 48,\nPtSn/nano–AlO Propane dehydrogenation 600 40\n2 3 164\nNat. Commun. 2025, 16,\nB-Ni in MnO Methane catalytic combustion 500 32\n2 1008\nIn summary, through comparative analysis, we found that our work exhibits a fundamental\ndifference in core innovation, synthetic approach, and the stability of the active centers compared to\npreviously reported work. It is not merely an incremental advancement of prior research but\nrepresents an entirely new concept. We present a new approach to achieve highly thermal-stable\nSACs by dispersing metal Pt into single atoms by liquid metal Ga, which is driven by the stable Pt–\nGa interaction even at elevated temperatures. This is a thermodynamically driven process, and the\ncorresponding mechanism was thoroughly evidenced from both thermodynamic and kinetic\nperspectives.\nChanges: For highlighting the advantages of our work, the stability of the reported SACs and\nours has been summarized as Supplementary Tab. 1 in the revised manuscript.\nComment 3: In addition, the experimental scope is rather narrow for a paper targeting Nature\nCommunications. The study focuses on a single reaction (ethane to ethylene) under relatively limited\nconditions, with a small set of catalyst formulations and without an in-depth kinetic analysis (e.g.\nan estimate of turnover frequencies per Pt vs. Ga, reaction orders) or operando characterization that\nwould firmly establish the structure and environment of the proposed Pt single atoms under working\nconditions. Long-term stability, deactivation pathways, and structure-performance relationships are\nnot explored to the depth one would expect for the broad readership of such a journal. The resulting\ndataset is essentially a proof of concept confined to one reaction and one composition space, which\nmay be more appropriate for a specialized catalysis journal.\nAuthor reply: Thank you very much for your constructive comments, which have significantly\nhelped us to enhance the depth and breadth of our work. In response to the concerns regarding the\nscope of our experiments, we have supplemented the systematic supplementary studies and\ndiscussions to analyze the applicability of the reaction system of our materials, reaction kinetic\nanalysis, the generalizability of our findings, and the long-term stability, deactivation pathways, and\nstructure-performance relationships. The detailed clarification is as follows:\n(1) Regarding the catalysis reaction applicability of this catalyst, EDH was chosen as a proof\nof concept, whose catalytic stability is highly sensitive to the dispersion state and coordination\nenvironment of the active metals (Angew. Chem. Int. Ed. 2024, 63, e202409784). Usually, when the\nsize of the active metals is increased, the coordination environment of each active atom is highly non-\nuniform. This will typically promote C−C cleavage and deep dehydrogenation side reactions, which\nseverely hinder the stability of the catalyst (ACS Catal. 2020, 10, 12932). Therefore, EDH serves as\nan exceptionally sensitive probe reaction for revealing the high-temperature stability of our\nliquid-metal-supported SACs.\nThe core innovation of our work lies in addressing the problem of severe sintering of SACs\noperated at high-temperature conditions in thermocatalysis by leveraging the fluidity and metal\naffinity of liquid metal. Profiting from the superior metal affinity of Ga with Pt, Pt–Pt bonds are\nbroken at elevated temperatures, and subsequently the mobile Pt atoms are captured by Ga to form\nthe stable Pt–Ga interaction, accomplishing the highly efficient dispersion of Pt single atoms.\nThe fluidity of liquid metal and the stable Pt–Ga interaction ensure that the Pt atoms can remain\ndynamically scattered throughout the whole liquid metal dispersion system. Additionally, liquid metal\ndispersed single atoms can self-update onto the catalysis interface continuously, promoting catalytic\nreactions at the interface. Hence, these liquid metal-dispersed SACs manifested remarkable thermal\ndurability and excellent ethylene selectivity for EDH.\nProfiting from the favorable stability of the synthesized SACs, this approach is anticipated\nto be extendable to other thermocatalysis reactions, such as CO₂ hydrogenation, reverse water-gas\nshift reactions, selective hydrogenation, coupling reactions, alkene epoxidation, and Fenton-like\nreactions, etc. These reactions occur under heating or even high-temperature conditions, imposing\nhigher demands on the thermal stability of catalysts. And multiple side reactions are prone to occur,\nnecessitating a highly uniform coordination environment around the catalytic active site to minimize\nor suppress the occurrence of these side reactions. Our strategy holds promise for achieving high\nstability and selectivity in these reactions. Accordingly, applying these catalysts to broader reaction\nsystems will be another major focus of our future work.\n(2) In terms of the catalyst formulations, the concept of liquid metal-dispersed SACs can be\napplied to synthesizing Rh-based SACs (Rh SACs@Ga/ZSM), and this catalyst also\ndemonstrates the improved EDH performance. In response to reviewer requests, we selected the\nGaRh system to demonstrate the universality of this approach for synthesizing liquid metal-dispersed\nSACs. XAFS analysis confirmed the formation of distinct Ga–Rh bonds (Fig. R5). Furthermore, the\nsynthesized Rh SACs@Ga/ZSM was employed in the EDH. The Rh SACs@Ga/ZSM-5 catalyst\nachieved an ethane conversion rate of 16.9% and an ethylene selectivity of 91.3% ( The atomic ratio\nof Ga and Rh in this catalyst is 99.8 : 0.2). While the Rh particles/ZSM-5 exhibited only 13.2%\nconversion and a mere 81.4% ethylene selectivity under the same amount of Rh (Fig. R6). Thus, the\nsynthesis method in our work exhibits certain applicability and can be extended to other catalyst\nformulations.\nFig. R5 | Normalized XANES spectra at the Rh K-edge (a) and FT Rh K-edge EXAFS spectra in R space\n(b) of liquid metal dispersed Rh SACs.\nFig. R6 | Catalyst performance of liquid metal dispersed Rh SACs and Rh particles. (a) Conversion of\nethane. (b) Selectivity of ethylene.\n(3) As for the catalytic test conditions and in-depth kinetic analysis, we have incorporated a\ncomprehensive intrinsic kinetic analysis within the currently prevalent temperature range for\nalkane dehydrogenation (Science 2024, 383, 998; Chem 2023, 9, 637; J. Am. Chem. Soc. 2024, 146,\n8939), including the turnover frequency (TOF), apparent activation energy (E ), and reaction order.\na\nThis not only further clarifies the advantages of liquid metal dispersed SACs in reaction kinetics, but\nalso verifies their catalytic activity at different temperatures and different reactant concentrations.\nThrough calculation, the TOF of the SACs is approximately 3.69 h⁻¹. The activation energy of Pt\nSACs@Ga/ZSM-5 for the EDH is about 102.44 kJ mol⁻¹, which is 34.74 kJ mol–1 lower than\nthat of the Pt particles/ZSM-5 catalyst. Furthermore, the ethane reaction order is comparable to\nthat of the Pt particles/ZSM-5 catalyst, with no significant difference in ethane adsorption.\na) TOF Calculation. The turnover frequency (TOF) for ethylene production was calculated using\nthe following equation:\n𝐹 ×𝐶𝑜𝑛𝑣. ×𝑆𝑒𝑙.\n𝑇𝑂𝐹 =\n𝐶2𝐻6 𝐶2𝐻6 𝐶2𝐻4\n𝑐2𝐻4 𝑚 ×𝜔 ×𝐷\n𝑐𝑎𝑡 𝑃𝑡 𝑃𝑡\nwhere 𝐹 , 𝐶𝑜𝑛𝑣. and 𝑆𝑒𝑙. represent the flow rate and conversion of ethane, the\n𝐶2𝐻6 𝐶2𝐻6 𝐶2𝐻4\nselectivity of ethylene, respectively. And 𝑚 represents the total mass of the catalyst. 𝜔\n𝑐𝑎𝑡 𝑃𝑡\nrepresents the total mass fraction of active metal Pt in the catalyst, which is determined by ICP-OES.\n𝐷 represent the dispersion of the active Pt on the surface of the catalyst. Based on the measurement\n𝑃𝑡\nof CO pulse adsorption, 𝐷 is approximately 13.96%. Based on these data, the calculated TOF for\n𝑃𝑡\nethylene over our catalyst is 3.69 h⁻¹.\nb) Determination of Activation Energy and Reaction Order. To investigate the kinetic\nbehavior of the catalyst for EDH, we measured reaction rates under conditions designed to minimize\ntransport limitations. Specifically, we limited the conversion to 5 ~ 15% while ensuring ethylene\nselectivity remained above 90% by systematically varying the catalyst amount. By analyzing the\ntemperature and pressure dependence of these rates, we extracted the activation energy and reaction\norder for the EDH.\nWe measured the ethane conversion in a temperature range between 883 K to 933 K and fitted\nthe data according to the Arrhenius equation to calculate the activation energy for EDH. The resulting\nactivation energy for the Pt SACs@Ga/ZSM-5 catalyst is 102.44 kJ mol–1 (Fig. R7a). For comparison,\nwe also calculated the apparent activation energy of the Pt particles/ZSM-5 in the EDH reaction.\nHowever, due to the poor selectivity of this catalyst, side reactions will inevitably occur. Therefore,\nwe only controlled its conversion rate to be within the range of 5 ~ 15%. The activation energy for\nthe extreme reaction is 137.18 kJ mol–1 (Fig. R7b). The significantly reduced activation energy\nindicates a greatly decreased energy barrier that needs to be overcome for the reaction to proceed.\nAnd the single-atom Pt formed in the liquid Ga can more effectively weaken the C–H bond of ethane\nthan Pt particles. Therefore, the Pt SACs@Ga/ZSM-5 catalyst exhibits more excellent catalytic\nperformance.\nFig. R7 | Arrhenius plots for EDH reaction. (a) Pt SACs@Ga/ZSM-5. (b) Pt particles/ZSM-5.\nThe ethane reaction order was determined under the condition where the total flow rate of the\nmixture of ethane and argon was 20 sccm, and the partial pressure of ethane was tested to be within\nthe range of 7.5 ~ 17.5%, and the temperature was constant at 923 K. The ethane reaction order for\nPt SACs@Ga/ZSM-5 catalyst was determined to be 1.097 (Fig. R8a), while the reaction order for Pt\nparticles/ZSM-5 catalyst is approximately 0.94 (Fig. R8b). The similar reaction order indicates that\nboth are comparable in their adsorption of ethane.\nFig. R8 | Effect of C H partial pressure on product distribution in EDH reaction. a Pt SACs@Ga/ZSM-\n2 6\n5. b Pt particles/ZSM-5.\n(4) In terms of the operando experiments, we attempted operando XAFS experiments. However,\ndue to the content of Pt being only 0.3 wt% in the Pt SACs@Ga/ZSM used for EDH reactions\ncompared to that of liquid metal Ga, the fluorescence signal intensity of Pt L edge is very weak (The\n3\natomic ratio of Ga and Pt in this catalyst is 99.8 : 0.2). Furthermore, the increased fluidity of liquid\nmetal at elevated temperatures will lead to severe scattering, which seriously interferes with the weak\noscillation signals related to the chemical state and local structure of elements (i.e., EXAFS\noscillation), reducing the signal-to-noise ratio and data quality. Therefore, the collection of the XAFS\nsignal in high-temperature operating conditions is extremely challenging.\nTo investigate the structure and environment of the proposed Pt single atoms under working\nconditions, we employed in situ XRD and XAFS measurements. The results indicate that Pt\nparticles spontaneously disperse in the liquid metal to form a stable Ga–Pt interaction at high\ntemperatures. During the in situ XRD measurements, initially, the characteristic peaks of Pt\nmetals can be apparently observed, which are located at 39.8o and 46.3o. With the temperature increasing,\nthe characteristic peaks of Pt metals were gradually weakened and disappeared subsequently, proving\nthe dispersion of Pt particles (Fig. R9). Besides, combined with ex situ synchrotron XAFS\nmeasurements before and after EDH tests for 100 hours, the results indicate that Pt maintains atomic-\nlevel dispersion after prolonged thermal stability testing (Fig. R10).\nFig. R9 | In situ XRD patterns of Pt@Ga on ZSM-5 in the process of heating up.\nFig. R10 | Normalized XANES spectra at the Pt L -edge and FT Pt L -edge EXAFS spectra in R space\n3 3\nof liquid catalyst before and after the ethane dehydrogenation.\n(5) To address the concerns about long-term stability, deactivation pathways, and structure–\nperformance relationships, we conducted a 100-hour on-stream stability test under reaction\nconditions, and the results show that both ethane conversion and propylene selectivity remain nearly\nunchanged without obvious deactivation (Fig. R11). Moreover, XAFS characterization of Pt\nSACs@Ga/ZSM-5 catalyst after the EDH for 100 hours confirms that Pt still maintains an atomic\ndispersion state in liquid metal, with no formation of Pt clusters or nanoparticles, and their local\ncoordination environment is consistent with that of the fresh catalyst (Fig. R10). Based on most\nprevious reports, it is widely believed that single atoms readily sinter into particles at high\ntemperatures, leading to decreased activity, while low selectivity can cause deep cracking side\nreactions (Acc. Chem. Res. 2013, 46, 1720; Phys.Chem.Chem.Phys., 2017, 19, 30513; Chem. Soc.\nRev., 2018, 47, 4314; Nat. Catal. 2025, 8, 1038). The stable catalytic performance of Pt\nSACs@Ga/ZSM-5 in this work indicates that the metal-metal interaction effectively stabilizes the Pt\nsingle atoms, completely suppressing the main deactivation pathways of Pt-based catalysts, such as\nsintering and coke deposition reported in previous studies.\nFig. R11 | Long-term stability test for ethane dehydrogenation performance of liquid metal dispersed\nSACs.\nThe SACs maintain high performance and excellent thermal stability at elevated temperatures\nwithout deactivation. The fundamental reason lies in the thermodynamically favorable process of\nliquid Pt dispersing within liquid metal at high temperatures. We elucidate the mechanism of this\nstability through theoretical calculations and machine learning.\na) Thermodynamic analysis reveals that Pt is more likely to exhibit as the single-atom\ndispersion state within Ga from the perspective of thermodynamics. The dispersed Pt atoms\ngenerally exhibit lower total energy compared to the aggregated Pt clusters within the simulated 10\nps (Fig. R12).\nFig. R12 | Theoretical calculations of heterogeneous active metal atoms monodispersed in liquid Ga. a,\nb The extracted 0 ps, 5 ps, and 10 ps snapshots from AIMD trajectories of both clustered (a) and dispersed (b)\nPt in liquid Ga. c Total energy versus time curves for the Ga Pt system containing clustered Pt and\n10 90 10 10\ndispersed Pt .\n10\nb) Dynamical simulations of Pt atom diffusion within Ga demonstrate that Pt atoms are\nresistant to aggregation. The actual existence state of Pt atoms in liquid Ga was studied using AIMD\nsimulations on the Ga Pt system (Pt dimer embedded in Ga ) at 923 K. The 10 ps NVT ensemble\n98 2 98\nsimulations (Fig. R13) demonstrate that the Pt–Pt interatomic distance progressively increases from\n4.18 Å to 11.63 Å, significantly exceeding the typical Pt–Pt bond length range of 2.65–2.79 Å (J.\nAm. Chem. Soc. 1978, 100, 2074). These results confirm that Pt atoms maintain stable single-atom states\nunder high temperature.\nFig. R13 | Time evolution of Pt–Pt interatomic distance in the Ga Pt system under NVT ensemble\n98 2\nsimulation.\nc) The statistical analysis of the dispersion state of Pt in the Pt–Ga catalyst. Furthermore, to\nmore intuitively demonstrate the single-atom state of Pt atoms in Ga, we trained a Ga–Pt\nneuroevolution potential model (which was updated in our revised manuscript as Supplementary Fig.\n9). Subsequently, we performed 20 ns NVT molecular dynamics simulations at 923 K on the\nGa Pt and Ga Pt structures using the trained Ga–Pt machine-learning potential. The\n2063 43 21342 43\nsimulation results clearly indicate that the Pt cluster rapidly disperses in liquid Ga (Fig. R14).\nover the last 10 ns (Fig. R15). In the Ga Pt structure, the proportion of mono-dispersed Pt was\n2063 43\n98.2%, while in the Ga Pt structure, it reached 99.9%. The results clearly demonstrate that in\n21342 43\nstructures with Pt content of 2 at% or below, Pt atoms can be considered fully mono-dispersed at 923\nK. To explore the dispersion state of Pt in Ga, we expanded the calculation system and analyzed the\nproportion of Pt in a single-atom state and the formation of Pt clusters in a larger model. Therefore,\nPt atoms exist as single atoms and do not undergo aggregation in the Pt–Ga catalyst.\nFig. R14 | The 20 ns NVT molecular dynamics simulations at 923 K on the Ga Pt and Ga Pt\n2063 43 21342 43\nstructures using the trained Ga–Pt machine-learning potential. Structural snapshots at different time points\nare shown with the side (xz) view. Dark blue and dark red spheres represent Ga and Pt atoms, respectively, and\nto better illustrate the single-atom state of Pt atoms, the size of Ga atoms has been relatively reduced.\nFig. R15 | The calculated proportions of mono-dispersed and dimerized Pt states in Ga Pt and\n2063 43\nGa Pt structures. Mono-dispersed Pt is defined as Pt atoms surrounded exclusively by Ga atoms within\n21342 43\na 3.2 Å range, while Dimerized Pt is defined as Pt atom that, within a 3.2 Å range, is surrounded by Ga atoms\nand exactly one additional Pt atom.\nChanges: We have incorporated testing of a comprehensive intrinsic kinetic analysis and\nverification of method universality into the revised manuscript, with supplementary information\nprovided in both the main text and Supplementary Information (Supplementary Figs. 27 ~ 29).\nPage 14–15 in revised manuscript:\nTo verify the universality of the strategy that liquid metals can disperse metals into single atoms,\nwe extended the synthesis method to other systems and successfully synthesized liquid metal\ndispersed Rh SACs (Supplementary Fig. 27). Moreover, Rh SACs@Ga/ZSM-5 exhibits significantly\nimproved catalytic performance compared to Rh particles/ZSM-5 in EDH (Supplementary Fig. 28).\nTo gain a deeper understanding of the effects of liquid metal dispersed SACs and nano catalysts\non the dehydrogenation reaction of ethane, we conducted kinetic studies on both types of catalysts.\nWe measured the ethane conversion rates in a temperature range of 883 ~ 933 K and fitted the data\naccording to the Arrhenius equation to calculate the activation energy for EDH. The apparent\nactivation energies for Pt SACs@Ga/ZSM-5 and Pt particles/ZSM-5 are 102.44 kJ mol⁻¹ and 137.18\nkJ mol⁻¹, respectively (Supplementary Fig. 29). The significantly reduced activation energy indicates\na greatly decreased energy barrier that needs to be overcome for the reaction to proceed. And the\nsingle Pt atom dispersed in the liquid Ga can more effectively weaken the C–H bond of ethane than\nPt particles. Therefore, the Pt SACs@Ga/ZSM-5 catalyst exhibits more excellent catalytic\nperformance.\nPage 34–36 in revised supplementary information:\nSupplementary Fig. 27 | Characterization of liquid metal dispersed Rh SACs. a Normalized XANES\nspectra at the Rh K-edge. b FT Rh K-edge EXAFS spectra in R space of liquid catalyst with phase correction.\nSupplementary Fig. 28 | Ethane dehydrogenation performance of liquid metal dispersed Rh SACs. a\nConversion of ethane. b Selectivity of ethylene.\nSupplementary Fig. 29 | Arrhenius plots for EDH reaction. a Pt SACs@Ga/ZSM-5. b Pt particles/ZSM-5.\nTo investigate the kinetic behavior of the catalyst for ethane dehydrogenation, it is necessary to minimize the\nlimitations of material transport as much as possible. Specifically, we limited the conversion to 5 ~ 15% while\nensuring ethylene selectivity remained above 90% by systematically varying the catalyst amount. However,\ndue to the poor selectivity of Pt particles/ZSM-5, side reactions are inevitable. Therefore, we only controlled\nits conversion rate to be within the range of 5 ~ 15%.\nComment 4: In summary, the manuscript is methodologically solid and the topic is of interest to\nthe catalysis community, but the incremental nature of the contribution, the limited experimental\nscope, the overstatement of conceptual novelty compared to the established SCALMS and SAC/SAA\nliterature, and the unconvincing treatment of the role of Pt versus Ga prevent me from viewing this\nas a strong candidate for publication in Nat. Commun. I therefore do not recommend publication of\nthis manuscript in its current form.\nAuthor reply: Thank you very much for your feedback on our revised manuscript. Our work\nproposed a solution for agglomeration of SACs in industrial thermal catalytic processes. This finding\nis substantiated through theoretical calculations and XAFS analysis before and after catalytic reaction.\nIt fundamentally differs from the innovations reported in previous SCALMS, SAC, and SAA studies.\nRegarding the roles of Pt and Ga, we re-conducted tests following your suggestion and found Pt\nto be the primary active site, while Ga does not directly contribute to the catalytic conversion.\nHowever, Ga enables Pt particles to disperse into Pt single atoms, achieving breakthroughs in\nselectivity and conversion. We have revised the data and descriptions in the paper accordingly.\nKinetic analysis further revealed that using liquid metal to disperse Pt from particles into single atoms\nsignificantly reduces the activation energy for the EDH reaction.\nTo address limitations in the experimental scope, we extended the system from Pt to Rh and\nconfirmed the universality of the synthesis strategy via XAFS. Catalytic activity was also validated\nthrough the EDH reaction, demonstrating superior selectivity and conversion rates compared to Rh\nparticles. We believe this approach has the potential to be extended to broader systems.\nWe are delighted to hear that you found the new version to be a significant improvement and that\nyour previous concerns have been fully addressed. We appreciate your recommendation for\npublication.\nTo Referee #5\nWe appreciate the referee's highly positive evaluation of our manuscript. We have made a point-\nby-point response to your comments and carefully revised the manuscript as you suggested. For your\nreference, please find our revisions marked in red.\nOverall remark: This manuscript reports a liquid metal catalytic system in which Pt dissolved\nin liquid Ga exhibits exceptionally stable performance in ethane dehydrogenation. Although the\nconcept of using liquid metals in catalysis is not entirely new, the remarkable long-term stability\ndemonstrated here is still appealing. The theoretical analysis, especially the MD simulations,\non the thermodynamic stability of the single-atom Pt species is also insightful. In my view, this work\nis suitable for publication in Nature Communications.\nAuthor reply: We are grateful for your great summary and approval of the novelty and\nsignificance of our work. According to your suggestions, we have carefully revised our manuscript.\nFor your reference, the revisions made in the revised manuscript are highlighted in red color and the\ndetailed point-by-point replies are listed below.\nComment 1: In Fig. 2e, the Pt–Pt interaction appears stronger than that of Pt–Ga. Why, then,\ndoes platinum remain atomically dispersed in liquid gallium? The authors argue that “The calculated\nbond dissociation energies show a clear ranking: E(Pt–Pt) (107.9 kcal/mol) > E(Ga–Pt) (74.9\nkcal/mol) > E(Ga–Ga) (32.5 kcal/mol). Crucially, the formation of two Ga–Pt bonds (149.8 kcal/mol)\nis energetically favored over either maintaining a Pt–Pt bond (107.9 kcal/mol) or the combined Pt–\nPt and Ga–Ga bonding (140.4 kcal/mol).” Yet, this explanation is not entirely convincing,\nbecause the numbers of the formed and dissociated bonds seem over simplified for the liquid phase.\nAuthor reply: Thank you for your constructive comment. As you have pointed out, compared to\nthe actual liquid Ga environment, merely considering the reaction Pt + Ga → 2PtGa is indeed a\n2 2\nsimplified approach. Actually, to better account for the liquid Ga environment, we have calculated\nthe formation energies and reaction energy barriers for embedding Ga atoms into Pt , (Ga Pt) ,\n2 6 2\nand (Ga Pt) clusters, which leads to the formation of Pt Ga, (Ga Pt) Ga, and (Ga Pt) Ga clusters. The\n7 2 2 6 2 7 2\nresults (Fig. R1) indicate that this process is both thermodynamically and kinetically feasible at 923\nK.\nFig. R1 | The formation energies and energy barriers associated with Ga atom insertion into Pt–Pt bonds\nin Pt Ga, (Ga Pt) Ga, and (Ga Pt) Ga molecular systems. The rough estimation suggests that the reaction\n2 6 2 7 2\ncan overcome an energy barrier of 67 Kcal mol–1 at 923 K.\nTo clarify the origin of this thermodynamic stability, the energy difference between breaking the\nGa–Ga and Pt–Pt bonds and forming two Ga-Pt bonds during this process was comparatively\nanalyzed. As your comment highlighted the oversimplification of the calculated model, we further\nincorporated the molecular structures of Pt , (Ga Pt) , (Ga Pt) , (Ga Pt) , (Ga Pt) , and\n2 1 2 2 2 3 2 4 2\n(Ga Pt) into our analysis (Fig. R2). Based on the optimized geometries, the Pt–Pt bond lengths in\n5 2\nthe stable structures of (Ga Pt) and (Ga Pt) are 3.101 Å and 3.380 Å, respectively. These values\n4 2 5 2\nsignificantly exceed 1.2 times the Pt–Pt bond length of 2.377 Å in Pt , indicating that the Pt–Pt bonds\n2\nin the stable configurations of (Ga Pt) and (Ga Pt) can be considered effectively broken. Therefore,\n4 2 5 2\nwe calculated the bond energy difference ∆E ( ∆𝐸 = 𝐸 +𝐸̅ −\nb 𝑏 (𝐺𝑎𝑛𝑃𝑡) 2 (𝑃𝑡−𝑃𝑡) 𝐺𝑎𝑛(𝐺𝑎−𝐺𝑎)\n2𝐸 ) for the Pt , (Ga Pt) , (Ga Pt) , and (Ga Pt) molecular clusters. Here, 𝐸̅\n𝐺𝑎𝑛+1𝑃𝑡(𝐺𝑎−𝑃𝑡) 2 1 2 2 2 3 2 𝐺𝑎𝑛(𝐺𝑎−𝐺𝑎)\nrepresents the average Ga–Ga bond energy in the Ga n molecular clusters, 𝐸 (𝐺𝑎𝑛𝑃𝑡)\n2\n(𝑃𝑡−𝑃𝑡) denotes the\nPt–Pt bond energy in the (Ga n Pt) 2 molecular clusters, and 𝐸 𝐺𝑎𝑛+1𝑃𝑡(𝐺𝑎−𝑃𝑡) refers to the Ga–Pt bond\nenergy in the Ga Pt molecular clusters. All bond energy calculations were corrected for basis set\nn+1\nsuperposition error (BSSE). The results, as shown in Fig. R3, indicate that the ∆E values for the\nb\nPt , (Ga Pt) , (Ga Pt) , and (Ga Pt) molecular clusters, evaluated using different computational\n2 1 2 2 2 3 2\nmethods (B3LYP, MN15L, and M06L), are all greater than zero. This demonstrates that in these\nmolecular systems, the Ga atoms involved in bond-breaking readily disrupt the Pt–Pt bonds,\nleading to the formation of stable Pt–Ga–Pt bridging units, thereby promoting the single-atom\ndispersion of Pt in liquid Ga.\nFig. R2 | The optimized structures of the molecular systems Pt , (Ga Pt) , (Ga Pt) , (Ga Pt) , (Ga Pt) ,\n2 1 2 2 2 3 2 4 2\nand (Ga Pt) . The red numbers denote the Pt–Pt bond lengths in angstroms (Å), and the blue numbers denote\n5 2\nthe relative energies (in kcal mol–1) of the three isomers of (Ga Pt) .\n4 2\nFig. R3 | The bond energy difference (∆E ). ∆E ( ∆𝐸 = 𝐸 +𝐸̅ −\nb 𝑏 (𝐺𝑎𝑛𝑃𝑡) 2 (𝑃𝑡−𝑃𝑡) 𝐺𝑎𝑛(𝐺𝑎−𝐺𝑎)\n2𝐸 ) was calculated using different computational methods (B3LYP, MN15L, and M06L) for the\n𝐺𝑎𝑛+1𝑃𝑡(𝐺𝑎−𝑃𝑡)\nPt , (Ga Pt) , (Ga Pt) , and (Ga Pt) molecular clusters.\n2 1 2 2 2 3 2\nChanges: In the revised version, we replaced the original simplified model (Pt + Ga → 2PtGa),\n2 2\nincorporated the molecular structures of Pt , (Ga Pt) , (Ga Pt) , (Ga Pt) , (Ga Pt) , and (Ga Pt) into\n2 1 2 2 2 3 2 4 2 5 2\nour analysis. And we calculated the bond energy difference to assess the stability of the Ga–Pt bond.\nThe changes are marked in red in the revised manuscript.\nPage 8 in the revised manuscript:\nTo fundamentally understand the thermodynamic preference for Pt mono-dispersion in liquid Ga,\nwe systematically calculated the bond energy difference ∆E ( ∆𝐸 = 𝐸 +\nb 𝑏 (𝐺𝑎𝑛𝑃𝑡) 2 (𝑃𝑡−𝑃𝑡)\n𝐸̅ −2𝐸 ) only for the Pt , (Ga Pt) , (Ga Pt) , and (Ga Pt) molecular clusters\n𝐺𝑎𝑛(𝐺𝑎−𝐺𝑎) 𝐺𝑎𝑛+1𝑃𝑡(𝐺𝑎−𝑃𝑡) 2 1 2 2 2 3 2\n(Fig. 2e and Supplementary Figs. 6 ~ 11). Here, 𝐸̅ represents the average Ga–Ga bond\n𝐺𝑎𝑛(𝐺𝑎−𝐺𝑎)\nenergy in the Ga molecular clusters, 𝐸 denotes the Pt–Pt bond energy in the (Ga Pt) \nn (𝐺𝑎𝑛𝑃𝑡)\n2\n(𝑃𝑡−𝑃𝑡) n 2\nmolecular clusters, and 𝐸 refers to the Ga–Pt bond energy in the Ga Pt molecular\n𝐺𝑎𝑛+1𝑃𝑡(𝐺𝑎−𝑃𝑡) n+1\nclusters. The results indicate that the ∆E values for the Pt , (Ga Pt) , (Ga Pt) , and (Ga Pt) molecular\nb 2 1 2 2 2 3 2\nclusters, evaluated using different computational methods (B3LYP, MN15L, and M06L), are all\ngreater than zero. This demonstrates that in these molecular systems, the Ga atoms involved in bond-\nbreaking readily disrupt the Pt–Pt bonds, leading to the formation of stable Pt–Ga–Pt bridging units,\nthereby promoting the single-atom dispersion of Pt in liquid Ga.\nFig. 2 | Theoretical calculations of heterogeneous active metal atoms monodispersed in liquid Ga. a, b\nThe extracted 0 ps, 5 ps, and 10 ps snapshots from AIMD trajectories of both dispersed (a) and clustered (b)\nPt in liquid Ga. c Total energy versus time curves for the Ga Pt system containing clustered Pt and\n10 90 10 10\ndispersed Pt . d Time evolution of Pt–Pt interatomic distance in the Ga Pt system under NVT ensemble\n10 98 2\nsimulation. e The calculated bond energy difference ∆E using different computational methods (B3LYP,\nb\nMN15L, and M06L) for the Pt , (Ga Pt) , (Ga Pt) , and (Ga Pt) molecular clusters. f The formation energies\n2 1 2 2 2 3 2\nand energy barriers associated with Ga atom insertion into Pt–Pt bonds in Pt Ga, (Ga Pt) Ga, and (Ga Pt) Ga\n2 6 2 7 2\nmolecular systems (the rough estimation suggests that the reaction can overcome an energy barrier of 67 kcal\nmol–1 at 923 K27). g The calculated proportions of mono-dispersed and dimerized Pt states in Ga Pt and\n2063 43\nGa Pt structures (Mono-dispersed Pt is defined as Pt atoms surrounded exclusively by Ga atoms within a\n21342 43\n3.2 Å range, while Dimerized Pt is defined as Pt atom that, within a 3.2 Å range, is surrounded by Ga atoms\nand exactly one additional Pt atom).\nPage 5 in revised supplementary information:\nTo gain further insight into the dispersion of Pt atoms in liquid Ga, we employed the\nB3LYP/LANL2DZ, MN15L/ LANL2DZ5 and M06L/ LANL2DZ methods to calculate the bond\nenergy difference ∆E (∆𝐸 = 𝐸 +𝐸̅ −2𝐸 ) only for the Pt ,\nb 𝑏 (𝐺𝑎𝑛𝑃𝑡) 2 (𝑃𝑡−𝑃𝑡) 𝐺𝑎𝑛(𝐺𝑎−𝐺𝑎) 𝐺𝑎𝑛+1𝑃𝑡(𝐺𝑎−𝑃𝑡) 2\n(Ga Pt) , (Ga Pt) , and (Ga Pt) molecular clusters. Here, 𝐸̅ represents the average Ga–\n1 2 2 2 3 2 𝐺𝑎𝑛(𝐺𝑎−𝐺𝑎)\nGa bond energy in the Ga molecular clusters, 𝐸 denotes the Pt–Pt bond energy in the\nn (𝐺𝑎𝑛𝑃𝑡)\n2\n(𝑃𝑡−𝑃𝑡)\n(Ga Pt) molecular clusters, and 𝐸 refers to the Ga–Pt bond energy in the Ga Pt\nn 2 𝐺𝑎𝑛+1𝑃𝑡(𝐺𝑎−𝑃𝑡) n+1\nmolecular clusters. All bond energy calculations were corrected for basis set superposition error\n(BSSE).\nPage 13–18 in revised supplementary information:\nSupplementary Fig. 6 | The optimized structures structures of the Ga , Ga , Ga , Ga , Ga , and Ga Pt\n2 3 4 5 6 7\nclusters.\nSupplementary Fig. 7 | The calculated dissociation energies of Ga–Ga bond in Ga , Ga , Ga , Ga , Ga ,\n2 3 4 5 6\nand Ga\n7\nclusters obtained using the B3LYP, MN15L, M06L, and CCSD methods. The Ga–Ga bond\nenergies in the Ga molecule calculated using the B3LYP, MN15L, M06L, and CCSD methods are 31.9, 23.6,\n2\n38.2, and 7.6 kcal mol–1, respectively. Among these, the B3LYP result (31.9 kcal mol–1) is closest to the\nexperimental value9 of 32.3 kcal mol–1, while the CCSD result deviates significantly from the experimental\nvalue, clearly indicating that the CCSD method is not suitable for simulating Ga–Pt systems. Furthermore, the\naverage Ga–Ga bond energies in Ga , Ga , Ga , Ga , Ga , and Ga clusters calculated using B3LYP, MN15L,\n2 3 4 5 6 7\nand M06L methods are 33.5, 31.2, and 37.8 kcal mol–1, respectively, demonstrating consistency among these\nthree methods.\nSupplementary Fig. 8 | The optimized structures of the molecular systems Pt , (Ga Pt) , (Ga Pt) ,\n2 1 2 2 2\n(Ga Pt) , (Ga Pt) , and (Ga Pt) . The red numbers denote the Pt-Pt bond lengths in angstroms (Å), and the\n3 2 4 2 5 2\nblue numbers denote the relative energies (in kcal mol–1) of the three isomers of (Ga Pt) . Based on the\n4 2\noptimized geometries, the Pt–Pt bond lengths in the stable structures of (Ga Pt) and (Ga Pt) are 3.101 Å and\n4 2 5 2\n3.380 Å, respectively. These values significantly exceed 1.2 times the Pt–Pt bond length of 2.377 Å in Pt ,\n2\nindicating that the Pt–Pt bonds in the stable configurations of (Ga Pt) and (Ga Pt) can be considered\n4 2 5 2\neffectively broken. Therefore, we calculated the bond energy difference ∆E only for the Pt , (Ga Pt) , (Ga Pt) ,\nb 2 1 2 2 2\nand (Ga Pt) molecular clusters.\n3 2\nSupplementary Fig. 9 | The calculated dissociation energies of Pt–Pt bond in Pt , (Ga Pt) , (Ga Pt) , and\n2 1 2 2 2\n(Ga Pt) clusters obtained using the B3LYP, MN15L, M06L methods. the Pt–Pt bond energies in (Ga Pt) ,\n3 2 1 2\n(Ga Pt) , and (Ga Pt) clusters calculated using B3LYP, MN15L, and M06L methods are similar, while the\n2 2 3 2\nPt–Pt bond energies in the Pt molecule calculated with these methods are 65.3, 101.0, and 74.4 kcal mol–1,\n2\nrespectively. Among these, the B3LYP and M06L results are close to the experimental value of 72.4 kcal mol–\n1[ref10].\nSupplementary Fig. 10 | The optimized structures of the molecular systems PtGa , PtGa , PtGa , and\n1 2 3\nPtGa .\n1 2 3\nPtGa clusters obtained using the B3LYP, MN15L, M06L methods.\nComment 2: On the other hand, the B3LYP functional is known to be less accurate for transition\nmetal dimers due to multi-configurational effects (see relevant references: Alvaro Posada-Borbón,\nAlvaro Posada-Amarillas, Theoretical DFT study of homonuclear and binary transition-metal dimers,\nChemical Physics Letters, 2015; Haoyu S. Yu, Xiao He, Donald G. Truhlar, MN15-L: A New Local\nExchange-Correlation Functional for Kohn–Sham Density Functional Theory with Broad Accuracy\nfor Atoms, Molecules, and Solids, J. Chem. Theory Comput. 2016.) Given this, are the results in Fig.\n2(e) sufficiently robust?\nAuthor reply: Thank you for your kind reminding. The electronic structures of transition metal\ndimers (e.g., Cr , Mn , Fe , Co , Ni , Cu ) exhibit considerable complexity due to the presence of\n2 2 2 2 2 2\nmultiple low-lying electron configurations. Consequently, the ground-state wave functions of these\nsystems cannot be adequately represented by a single Slater determinant, rendering single-reference\nmethods insufficient. These systems are characterized by pronounced strong electron correlation and\nsubstantive multiconfigurational character. For their accurate theoretical description, it is essential to\nemploy multireference approaches, such as CASSCF/CASPT2 or MRCI. Though density functional\ntheory (DFT) lacks a priori accuracy guarantees, its computational cost is significantly lower than\nthat of multireference methods. Moreover, DFT methods have been widely applied to transition metal\nmolecular systems for predicting molecular structures, vibrational frequencies, absorption spectra,\ntransition-state structures, electron affinities, as well as thermochemical data (Cramer, C. J., Truhlar,\nD. G. Density functional theory for transition metals and transition metal chemistry. Phys. Chem.\nChem. Phys. 2009, 11, 10757). Among the various DFT methods, the B3LYP method is a widely used\napproach (Lee, C., Yang, W., Parr, R. G. Development of the Colle-Salvetti correlation-energy\nformula into a functional of the electron density. Phys. Rev. B 1988, 37, 785). Moreover, in the\nreference you mentioned, “Posada-Borbón, A., Posada-Amarillas, A. Theoretical DFT study of\nhomonuclear and binary transition-metal dimers. Chem. Phys. Lett. 2015, 618, 66” the authors point\nout that the B3LYP method performs well in describing experimental dissociation energy values for\nPd–Au and Pt–Ni dimers, and the calculated equilibrium bond length r (Å) and harmonic frequency\nω (cm–1) for the Pt dimer are 2.382 and 229.37, respectively, which are also in close agreement with\n2\nthe experimental values of 2.333 and 222.46. Additionally, since Ga is a main group metal element,\nthe B3LYP computational method is entirely applicable. Therefore, the B3LYP method can, to some\nextent, be used for the Ga–Pt binary system we intend to study. Meanwhile, considering the paper\nyou recommended, “Yu, H. S., He, X., Truhlar, D. G. MN15-L: A new local exchange-correlation\nfunctional for Kohn–Sham density functional theory with broad accuracy for atoms, molecules, and\nsolids. J. Chem. Theory Comput. 2016, 12, 1280” we will employ hybrid functional (B3LYP),\nmeta-GGA (MN15L and M06L), and coupled-cluster methods (CCSD(T)) to calculate the dissociation\nenergies of different Ga–Pt systems.\nFirst, as shown in Fig. R4, the Ga–Ga bond energies in the Ga molecule calculated using the\nAmong these, the B3LYP result (31.9 kcal mol–1) is closest to the experimental value of 32.3 kcal\nmol–1 (Himmel, H. J., Gaertner, B. Characterization of Isolated Ga Molecules by Resonance Raman\nresult deviates significantly from the experimental value, clearly indicating that the CCSD method is\nnot suitable for simulating Ga–Pt systems. Furthermore, the average Ga–Ga bond energies in Ga ,\n3 4 5 6 7\n31.2, and 37.8 kcal mol–1, respectively, demonstrating consistency among these three methods.\nAdditionally, as shown in Fig. R5, the Pt–Pt bond energies in (Ga Pt) , (Ga Pt) , and (Ga Pt) clusters\n1 2 2 2 3 2\ncalculated using B3LYP, MN15L, and M06L methods are similar, while the Pt–Pt bond energies in\nthe Pt molecule calculated with these methods are 65.3, 101.0, and 74.4 kcal mol–1, respectively.\n(Taylor, S., Lemire, G. W., Hamrick, Y. M., et al. Resonant two-photon ionization spectroscopy of\njet-cooled Pt . J. Chem. Phys. 1988, 89, 5517). Finally, as shown in Fig. R6, the Ga–Pt bond energies\n2\nin PtGa , PtGa , PtGa , and PtGa clusters calculated using B3LYP, MN15L, and M06L methods are\n1 2 3 4\nalso similar. Overall, among the three methods (B3LYP, MN15L, and M06L), the B3LYP method\nstands out as particularly effective in accurately simulating the intermolecular interaction\nenergies within Ga–Pt binary metal systems. Therefore, the relevant results calculated using the\nB3LYP method are reliable.\nFig. R4 | The calculated dissociation energies of the Ga–Ga bond in Ga , Ga , Ga , Ga , Ga , and Ga\n2 3 4 5 6 7\nclusters. The calculated dissociation energies were obtained using the B3LYP, MN15L, M06L, and CCSD\nmethods. The dashed line indicates that the dissociation energy of the Ga–Ga bond in Ga₂ is 32.3 kcal mol–1.\nFig. R5 | The calculated dissociation energies of the Pt–Pt bond in Pt , (Ga Pt) , (Ga Pt) , and (Ga Pt)\n2 1 2 2 2 3 2\nclusters. The calculated dissociation energies were obtained using the B3LYP, MN15L, and M06L methods.\nThe dashed line indicates that the dissociation energy of the Ga–Ga bond in Ga₂ is 72.4 kcal mol–1.\nFig. R6 | The calculated dissociation energies of the Ga–Pt bond in PtGa , PtGa , PtGa , and PtGa\n1 2 3 4\nclusters. The calculated dissociation energies were obtained using the B3LYP, MN15L, and M06L methods.\nChanges: We employed three computational methods (B3LYP, MN15L, and M06L) to\ndemonstrate the reliability of selecting the B3LYP method for calculations. The changes are marked\nin red in the revised manuscript (Supplementary Fig. 6–11).\nComment 3: Additionally, what is the turnover frequency (TOF) normalized by the mass of Pt?\nThis information is crucial for evaluating the atomic efficiency and cost-effectiveness of the catalyst,\ngiven the high price of platinum?\nAuthor reply: Thank you very much for your valuable suggestions. We agree that the mass-based\nTOF is an indispensable parameter for assessing the economic viability of Pt-based catalysts.\nAccording to your suggestion, we supplemented the corresponding experiments and calculated the\nTOF value normalized by the mass of Pt. Furthermore, we analyze the cost of Pt SACs@Ga/ZSM-5, Pt\nparticles/ZSM-5 catalyst, and pure Pt to evaluate the commercial potential of our catalyst.\n(1) TOF Calculation. The turnover frequency (TOF) for ethylene production was calculated\nusing the following equation:\n𝐹 ×𝐶𝑜𝑛𝑣. ×𝑆𝑒𝑙.\n𝑇𝑂𝐹 =\n𝐶2𝐻6 𝐶2𝐻6 𝐶2𝐻4\n𝑐2𝐻4 𝑚 ×𝜔 ×𝐷\n𝑐𝑎𝑡 𝑃𝑡 𝑃𝑡\nwhere 𝐹 , 𝐶𝑜𝑛𝑣. and 𝑆𝑒𝑙. represent the flow rate and conversion of ethane, and the\n𝐶2𝐻6 𝐶2𝐻6 𝐶2𝐻4\nselectivity of ethylene, respectively. And 𝑚 represents the total mass of the catalyst. 𝜔\n𝑐𝑎𝑡 𝑃𝑡\nrepresents the total mass fraction of active metal Pt in the catalyst, which is determined by ICP-OES.\n𝐷 represent the dispersion of the active Pt on the surface of the catalyst. Based on the measurement\n𝑃𝑡\nof CO pulse adsorption, 𝐷 is approximately 13.96%. Based on these data, the calculated TOF for\n𝑃𝑡\nethylene over our catalyst is 3.69 h⁻¹.\n(2) Cost analyses. Based on the calculation methods of the reference, a comprehensive cost\nanalysis was conducted to evaluate the commercial potential of our catalyst (Sci. Adv. 2025, 11,\neadt9037). The total cost to produce 10 kg of three different catalysts was determined using current\nglobal metal prices and supplier quotations, with the calculation methodology detailed below. As\nsummarized in Tab. R1 and illustrated in Fig. R7, our catalyst achieves a cost reduction relative to\nthe pure Pt catalyst. Notably, it also undercuts the cost of a conventional Pt particles/ZSM-5 catalyst\nby an additional 9.2%, while delivering enhanced selectivity and conversion.\nTab. R1 | The total cost to produce 10 kg of three different catalysts. The prices of Pt and Ga are from the\nwebsite: https://www.dailymetalprice.com/metalpricecharts.php, and the price of ZSM-5 is from Aladdin’s\nselling price (https://www.aladdin-e.com/zh_cn/m196697.html#citations-of-this-product).\nMaterials cost (US$)\nMass of Total cost\nType of catalyst\ncatalyst (US$)\nPt ZSM-5 Ga\nPure Pt 607,607.1 / / 607,607.1\nPt particles/ZSM-5 10 kg 1,822.8 3, 379.1 / 5,201.9\nPt SACs@Ga/ZSM-5 1,822.8 1,830.2 1,067.3 4,720.3\nFig. R7 | The total cost to produce 10 kg of three different catalysts. The prices of Pt and Ga are from the\nwebsite: https://www.dailymetalprice.com/metalpricecharts.php, and the price of ZSM-5 is from Aladdin's\nselling price (https://www.aladdin-e.com/zh_cn/m196697.html#citations-of-this-product)\nCost analysis details:\n1) Pure Pt\nPt price = US$ 60,760.71/kg (as of Dec 09, 2025)\n10 kg of catalyst = 10 kg × US$ 60,760.71/kg = US$ 607,607.1\nTotal material cost = US$ 607,607.1\nNote: The average price of Pt is approximately US$ 1701.30 oz = US$ 60,760.71 kg (as of Dec\n09, 2025)\nhttps://www.dailymetalprice.com/metalpricecharts.php\n2) Pt particles/ZSM-5\nThe amount of Pt used in Pt particles/ZSM-5 and Pt SACs@Ga/ZSM-5 catalyst is the same.\nCost Calculation for Pt particles/ZSM-5 Catalyst:\nCost of Pt price = 0.3% × 10 kg × US$ 60,760.71/kg = US$ 1,822.8 (as of Dec 09, 2025)\nCost of ZSM-5 molecular sieve = 99.7%× 10 kg × RMB¥ 2398/kg ÷ 7.0753 = US$3,379.1 (see\nnote below)\nTotal material cost =US$ 1,822.8 (Pt) + US$ 3,379.1 (ZSM-5) = US$ 5,201.9\nNote: Prices are approximate and may vary based on supplier, purity, and purchase quantity. Bulk\nquantity purchase will reduce the cost.\ni) ZSM-5 molecular sieve is a specialized chemical, and Aladdinh offers ZSM-5 molecular sieve\nat RMB¥ 1199 for 500 grams, equating to RMB¥ 2398/kg (as of Dec 09, 2025)\nhttps://www.aladdin-e.com/zh_cn/m196697.html#citations-of-this-product\nii) According to the exchange rate announced by the Bank of China, the exchange rate between\nthe US dollar and the Chinese yuan is: RMB¥ 7.0753 ≈ US$ 1 (as of Dec 10, 2025)\nhttps://www.chinamoney.com.cn/chinese/sddshl/\n3) Pt SACs@Ga/ZSM-5\nThis catalyst contains 0.3 wt% Pt (The atomic ratio of the liquid catalyst is Ga : Pt = 99.8 : 0.2)\nCost Calculation for Pt SACs@Ga/ZSM-5 Catalyst:\nCost of Pt price = 0.3% × 10 kg × US$ 60,760.71/kg = US$ 1,822.8\nCost of Ga price = 45.7% × 10 kg ×US$ 233.54 kg = US$ 1,067.3\nCost of ZSM-5 molecular sieve = 54.0%× 10 kg × RMB¥ 2398/kg ÷ 7.0753 = US$ 1830.2 (see\nnote below)\nTotal material cost =US$ 1,822.8 (Pt) + US$ 1,067.3 (Ga) + US$ 1830.2 (ZSM-5) = US$ 4720.3\nNote: The average price of Ga is approximately US $233.54 kg (as of Dec 09, 2025)\nhttps://www.dailymetalprice.com/metalpricecharts.php"}]

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