Microporous MOF for simultaneous high thermodynamic and kinetic synergistic separation of propylene and propane

Domain: biology
Published: 2026-03-23
Editorial outcome: minor_revision

Abstract
Efficient separation of propylene from propane is a critical yet challenging industrial process. While rigid molecular sieves offer ideal selectivity, their narrow nanopores inherently constrain adsorption capacity and diffusion kinetics due to compromised thermodynamic-kinetic trade-offs. To address this, we report ZSTU-10, a molecular sieve constructed via structure-directing agents. Uniquely, ZSTU-10 features localized sieving gates for selective guest admission, expansive diffusion channels for rapid transport, and central pore cavities for high-capacity storage. This gate-channel-cavity architecture enables the precise exclusion of propane while facilitating the dense packing and fast diffusion of propylene, achieving simultaneous thermodynamic-kinetics optimization in molecular sieving. Static adsorption experiments demonstrate an exceptional propylene uptake (97.7 cm3 cm-3) at 298 K and 1 bar. Time-dependent uptake kinetics revealed a propylene diffusion coefficient (4.29 × 10-9 cm2 s-1) in ZSTU-10 surpassing benchmarks by two orders of magnitude. Dynamic breakthrough experiments demonstrate that ZSTU-10 produces high-purity propylene (99.1%) with a productivity of 37.5 L kg−1 in a single adsorption-desorption cycle.

Introduction
Propylene is one of the most crucial olefins in the petrochemistry industry that serves as a primary feedstock for manufacturing various consumer products and chemicals1,2. Industrial propylene (C3H6) is mainly produced via steam cracking of naphtha or fluid catalytic cracking by hydrocarbons, with propane (C3H8) as a by-product3-5. The established industrial route to obtain high-purity C3H6 (> 99.5%) from C3H6/C3H8 mixtures relies on traditional thermal-driven cryogenic distillation, which is highly energy intensive separation due to the small volatility difference between the two molecules6-9. Therefore, it is imperative to develop alternative separation technologies with lower energy input and reduced capital cost. Porous materials including zeolites10-16, activated carbons17,18, and metal-organic frameworks (MOFs)19-21 have garnered considerable attention as non-thermal separation platforms, offering the potential to markedly reduce energy consumption relative to cryogenic distillation. However, conventional zeolites and activated carbons often face limitations in simultaneously achieving high selectivity, high working capacity, and fast mass transport for the challenging C3H6/C3H8 mixtures, owing to restricted pore-size tunability or broad pore-size distributions. In contrast, MOFs provide highly programmable pore environments and precisely engineerable adsorption sites, enabling rational design of molecular-sieving apertures and host–guest interactions, which has led to their extensively studied for olefin/alkane separation22-26.

MOFs utilizing thermodynamic separation principles exploit differences in adsorption affinity (e.g., via open metal sites) to achieve high equilibrium selectivity27,28. However, the strong host-guest interactions in such materials often necessitate substantial energy for regeneration. In contrast, kinetic separations rely on the differences in diffusion rates and typically feature tuned pore apertures and smooth surfaces to minimize transport resistance29-32. Consequently, this approach often suffers from weak host-guest confinement, failing to discriminate between closely related alkanes/alkenes and resulting in low selectivity. While molecular sieving MOFs achieve ultra-high selectivity as an extreme form of kinetic separation, enabled by precise size discrimination within small-sized guests33-36. Yet, they face an inherent structural paradox that the narrowly confined channels intrinsically limit adsorbate diffusion kinetics and reduce accessible adsorption capacity37,38. Furthermore, while elevated temperatures can enhance molecular mobility to mitigate diffusion constraints, they simultaneously reduce adsorption capacity due to exothermic thermodynamic effects. Resolving incompatibilities between pore size and pore shape of MOFs and the optimal operational conditions to achieve synergistic thermodynamic-kinetic separation remains a fundamental challenge39-42. To address these constraints, we develop a solvent-templated nanoconfinement strategy that precisely tailors MOF pore apertures (in the 3-5 Å regime) and optimizes process conditions (e.g., temperature) to achieve a thermodynamically-kinetically balanced separation. The resulting framework integrates localized molecular sieving gate to selective guest admission, interconnected auxiliary large channels that function as bridge-mediated guest diffusion pathways, and central cavity acting as high-capacity storage reservoirs. This gate-channel-cavity architecture cooperatively enhances diffusion kinetics, guest storage capacity, and host-guest binding affinities (Fig. 1).

Herein, using N-butyl alcohol/N-propyl alcohol /Isopropyl alcohol (n-BuOH/n-PrOH/i-PrOH) as solvent templates, we constructed three isoreticular ultra-microporous MOFs (denoted ZSTU-10, ZSTU-11, and ZSTU-12). These isostructural MOFs feature central pore cages radially connected to constricted gate apertures via diffusion channels, forming an interpenetrated three-dimensional (3D) channel system. Notably, the effective gate aperture of ZSTU-10 precisely interposes between the minimum cross-sections of C3H6 (3.8 × 4.1 Å2) and C3H8 (3.3 × 4.2 Å2), enabling molecular sieving via size exclusion. Gas adsorption analyses reveal a high volumetric C3H6 uptake (97.7 cm3 cm-3) and a notable combined C3H6/C3H8 equilibrium-kinetic selectivity of 2 × 103. The C3H6 diffusion coefficient (4.29 × 10-9 cm2 s-1) rivals benchmark ZU-609 material, while the pronounced C3H6/C3H8 diffusion-rate differentiation is attributed to the cooperative effect of the localized sieving gate and the short, low-resistance diffusion pathways. Dynamic breakthrough experiments reveal that ZSTU-10 is capable of obtaining high-purity C3H6 (99.1%) with a productivity of 37.5 L kg-1. Crystallography studies and neutron powder diffraction experiments confirm this unique framework of ZSTU-10 overcomes intrinsic constraints to achieve high adsorption capacity, rapid diffusion kinetics, and ideal host-guest interactions.

Results
Synthesis and characterization
Colorless, rectangular prismatic crystals of ZSTU-10, ZSTU-11, and ZSTU-12 were synthesized via a solvothermal reaction involving zinc carbonate (ZnCO3), 1,2,4-1H-triazole (TRZ), and oxalic acid in a solvent mixture of water (H2O) and n-BuOH/n-PrOH/i-PrOH (Fig. 2a). Single-crystal X-ray diffraction (SCXRD) reveals that three isoreticular MOFs crystallize in the monoclinic P21/c space group, with symmetrical building blocks comprising Zn nodes and organic linkers arranged systematically (Supplementary Table 1). In all three structures, each pentahedral Zn center is coordinated by three nitrogen atoms from three distinct triazolate linkers and two oxygen atoms from a single oxalate ligand. The planar conjugation of triazoles facilitates their preferential coordination with Zn, forming two-dimensional 2D layered [Zn(TRZ)]n. These layers are subsequently pillared by oxalate units to form a three-dimensional (3D) framework with a dmc topology (Supplementary Fig. 1), which is isostructural to the benchmark CALF-20 framework known for its high stability43. The solvent-accessible voids for ZSTU-10, ZSTU-11 and ZSTU-12, as determined by the PLATON program, are 40.2%, 40.4% and 40.1%, respectively. The powder X-ray diffraction (PXRD) patterns of the as-synthesized samples match well with the simulated patterns, verifying their superior bulk phase purity and crystallinity (Supplementary Figs. 13-14). Notably, the PXRD patterns reveal a progressive shift of the peak for the (100) planes to lower 2θ values from ZSTU-10 to ZSTU-12. An in-depth examination confirmed that the template solvents induce subtle structural variations in bond angles and lengths. The quantitative ∠N-Zn-O angles are 164.68°, 164.80°, and 165.09°, while the angles of adjacent triazoles are 98.60°, 99.37° and 97.48° for ZSTU-10, ZSTU-11, and ZSTU-12, respectively (Fig. 2b-d and Supplementary Fig. 5). These geometric variations effectively modulate the gate apertures and channel cross-sections.

SCXRD analysis, visualized via Connolly surface, demonstrates that ZSTU-10 features a center nanocage interconnected with surrounding diffusion channels. It possesses an optimal sieving gate of 4.4 × 3.4 Å2 aligned with the crystallographic c axis (Fig. 2f), with an intermediate estimated cross-section area of 14.96 Å2, which is substantially larger than the minimum cross-section of C3H6 (13.86 Å2) yet smaller than that of C3H8 (15.58 Å2). By comparison, the gates in ZSTU-11 and ZSTU-12, with aperture dimensions of 4.9 × 3.1 Å2, and 4.6 × 2.9 Å2, either fails to recognize guests or blocks their entry (Supplementary Fig. 3-4). Since the gate aperture serves as the dominant geometric determinant for sieving selectivity, these structural differences suggest that ZSTU-10 exhibits a potential size-selective sieving effect on C3H6 and C3H8. Furthermore, the built-in large channels facilitate the rapid transport of guests into the central cavities, firmly locking them in place, which is crucial for prompting adsorbate diffusion and storage capacity.

ZSTU-10 possesses a sufficiently large cavity with dimensions of 8.5 × 6.3 × 6.5 Å3, interconnected on all sides by diffusion channels 4.7 × 3.0 Å2 (Fig. 2e and Supplementary Fig. 2). Such channel dimensions are sufficiently open to facilitate fast C3H6 diffusion, while the cage volume supports high packing density and thus high volumetric uptake. This comprehensive structural analysis suggests that ZSTU-10 possesses the optimal pore aperture and channel for C3 separation.

The structural robustness and phase identify of the ZSTU series were rigorously validated through complementary diffraction techniques and solvent-stability assays. To assess framework integrity upon activation, high-resolution neutron powder diffraction (NPD) was employed to characterize ZSTU-10/11/12. The NPD profiles of the as-synthesized and activated samples (ZSTU-10a/11a/12a) exhibit high structural uniformity with negligible deviation. (Supplementary Figs. 6-8 and Supplementary Figs. 11-12 and Supplementary Figs. 15-16). This structural invariance confirm that precise coordination environment and pore apertures are preserved without framework relaxation or collapse following the thorough evacuation of solvent molecules. Furthermore, systematic cross-solvent soaking experiments were conducted. Each material was immersed in the specific alcohols used for the synthesis of its isoreticular counterparts to evaluate potential phase transitions. The resulting PXRD patterns remained entirely unchanged (Supplementary Fig. 18), demonstrating that these frameworks do not undergo solvent-mediated interconversion. All ORTEP-style illustrations of ZSTU-10/11/12 were showed in the Supplementary Figs. 74-82. These results collectively confirm that the three isoreticular structures are independent stable states, whose specific pore metrics are inherent to the alcohol-templated assembly rather than reflecting meta-stable intermediates.

Porosity analyses and thermodynamic equilibrium adsorption
Thermogravimetric analysis indicates that all three MOFs maintain thermal stability up to 400 ℃. The initial weight loss steps correspond well with the evaporation temperatures of the respective solvent templates (Supplementary Fig. 10). Subsequently, the permanent porosity of ZSTU-10, ZSTU-11, and ZSTU-12 was evaluated by carbon dioxide (CO2) adsorption isotherms at 195 K and nitrogen (N2) adsorption isotherms at 77 K (Supplementary Figs. 22-24). Both ZSTU-10 and ZSTU-11 exhibit type-Ⅰ adsorption behaviors for CO2 and N2, whereas ZSTU-12 shows reversible type-Ⅰ CO2 adsorption isotherm but negligible N2 uptake at 77 K, which is attributed to the kinetic restriction of N2 diffusion through the narrower gate aperture in ZSTU-12. Based on N2 adsorption isotherms at 77 K, the Brunauer−Emmett−Teller (BET) surface areas of ZSTU-10 and ZSTU-11 were determined to be 406.2 m2 g-1 and 419.8 m2 g-1, respectively (Supplementary Fig. 25). The corresponding total pore volume were determined to be 0.18 cm3 g-1 and 0.249 cm3 g-1. For ZSTU-12, its microporous nature is confirmed by a CO2 uptake of 62.5 cm3 g-1 at 195 K, with an apparent surface area of 180 m2 g-1 and a total pore volume of 0.097 cm3 g-1. The pore size distribution for ZSTU-10, derived from the N2 adsorption isotherm at 77 K, is narrowly centered at 3.9 Å based on Horváth-Kawazoe (H-K) model, consistent with an ultra-microporous gate-dominated framework.

Motivated by their distinct gate apertures and large cavities, we investigated the adsorption performance of C3H6 and C3H8 in three MOFs. Single-component adsorption isotherms of C3H6 and C3H8 on ZSTU-10, ZSTU-11, and ZSTU-12 were collected at 298 K and 1 bar (Figs. 3a-b and Supplementary Fig. 39). ZSTU-11 demonstrates substantial adsorption capacity for both C3H6 and C3H8, which is attributed to its larger pore aperture that lacks size discrimination. In contrast, ZSTU-12 exhibited minimal adsorption for either gas across various temperatures, indicating kinetic blockage due to its constricted pores. Notably, ZSTU-10 exhibited a steep uptake of C3H6 and quickly reached equilibrium at low pressure, while completely excluded C3H8. ZSTU-10 achieved a significant C3H6 volumetric uptake of 92.5 cm3 cm-3 (57.0 cm3 g-1) at 0.1 bar and 298 K and reached a plateau at higher pressures. This exceptionally high low-pressure uptake is attributed to the synergistic effect of strong binding sites within the central cavity and rapid transport through diffusion channels, which was a common adsorption phenomenon observed in advanced adsorbents designed for high-affinity gas capture44. At 298 K and 1 bar, The C3H6 adsorption capacity reaches 97.7 cm3 cm-3 (60.9 cm3 g-1), reflecting its superior packing efficiency. The excellent C3H6 uptake of ZSTU-10 surpasses many benchmark sieving materials, such as ZU-609 (73.1/10.8 cm3 cm-3)45, Y-abtc (63/35 cm3 cm-3)37, Co-gallate (66.6/17.9 cm3 cm-3)38, JNU-3a (87.5/18.7 cm3 cm-3)35, KAUST-7 (61.9/10.1 cm3 cm-3)45-48 at 1 bar and 0.1 bar (Fig. 3c and Supplementary Table 11). Due to negligible adsorption of C3H8, ZSTU-10 possessed a significantly higher C3H6/C3H8 uptake ratio of 24.5, placing it among the top-performing materials (Supplementary Fig. 35)49. Remarkably, based on the absorbed C3H6 amount and the experimental pore volume, the packing density of C3H6 within ZSTU-10 is estimated to be 633 g L-1, which approaches the density of liquid C3H6 (608 g L-1) at its boiling point of 225 K and exceeds gaseous C3H6 at 298 K and 1 bar (1.707 g L-1) by a factor of approximately 370 times (Supplementary Fig. 34). These results indicate exceptionally efficient pore filling enabled by the optimized gate–channel–cavity architecture of ZSTU-10.

The ideal absorbed solution theory (IAST) was employed to evaluate the adsorption selectivity for an equimolar C3H6/C3H8 mixture, revealing an exceptionally high selectivity of 7 × 103 for ZSTU-10 (Supplementary Figs. 30-33 and Supplementary Table 11). Due to the ultralow capacity and the difficulty in achieving equilibrium for C3H8, fitting parameters of IAST selectivity for molecular sieving present certain uncertainties and errors that need to be acknowledged (Supplementary Tables 7-8). Encouraged by the outstanding low-pressure adsorption behaviors of ZSTU-10, Henry’s constant of C3H6 and C3H8, along with Henry’s selectivity were subsequently calculated based on the sorption isotherms across the entire pressure range with Langmuir fitting methods (Supplementary Fig. 36 and Supplementary Table 3)50-52. The Henry’s constant of C3H6 was estimated to be 174.3 mmol g-1 kPa-1 for ZSTU-10, and Henry’s selectivity was determined to be 124, considering the low Henry’s constant of C3H8 for ZSTU-10 (1.4 mmol g-1 kPa-1). This value far exceeds that of many C3H6-selective adsorbents, including DL-mal-MOF (5.86)42, and MAF-23-O (8.16)39, and Mg-MOF-74 (18.7)50 (Supplementary Fig. 37). Based on the adsorption isotherms at 313, 323 and 333 K, the isosteric heat of adsorption (Qst) of C3H6 on ZSTU-10 was calculated to be 45.5 kJ mol-1 at zero coverage using the virial method. For comparison, The Qst of C3H6 on ZSTU-11 is 37.3 kJ mol-1 according to C3H6 adsorption isotherms at 303, 313 and 323 K (Supplementary Figs. 26-29). The moderate adsorption enthalpy of ZSTU-10 indicates an energy-efficient regeneration process.

Adsorption kinetics
It is well established that the overall adsorption performance is governed not only by thermodynamic equilibrium factors, such as host-guest affinity and adsorption enthalpy, but also by the diffusion kinetics of guest molecules within the framework. An initial analysis of the structural features of the centered cage with diffusion channels in ZSTU-10 suggests that it is ideally configured to support the rapid kinetics of C3H6 molecules. To explore its kinetic advantage, time-dependent kinetic adsorption isotherms of ZSTU-10 and ZSTU-11 were measured from 283 K to 318 K at 1 bar (Supplementary Figs. 49-50). Remarkable differences in the diffusion coefficients of C3H6 and C3H8 were observed, with C3H6 diffusing much faster than C3H8, leading to an impressive kinetic selectivity of 286 for ZSTU-10 (Supplementary Fig. 38 and Supplementary Figs. 51-52 and Supplementary Tables 4-5). To further quantify this distinction, the calculated diffusion coefficient of C3H6 in ZSTU-10 was 4.29 × 10-9 cm2 s-1 at 298 K and 1 bar. This value is comparable to ZU-609 (1.36 × 10-9 cm2 s-1), and two orders of magnitude higher than other leading sieving materials such as Co-gallate (6.47 × 10-11 cm2 s-1), and KAUST-7 (9.49 × 10-11 cm2 s-1) (Fig. 3f and Supplementary Fig. 9 and Figs. 53-54 and Supplementary Table 6)53. By combining this superior kinetics adsorption with the aforementioned thermodynamic equilibrium performances, ZSTU-10 achieves a more standard equilibrium-kinetic combined selectivity, which is up to 2 × 103. Such a high selectivity significantly outperforms most benchmark MOFs, such as DL-mal-MOF (62.6)42, MAF-23-O (68.8)39, Ni(AIP)(PBPY) (48.3)54 (Supplementary Table 10)55.

In an unexpected finding, the static equilibrium adsorption displayed a pattern that deviated from conventional exothermic principles. As a result, pure-component adsorption/desorption isotherms were measured for C3H6 and C3H8 over a temperature range from 243 K to 333 K (Supplementary Figs. 40-48). With the increase of temperature, the results revealed a volcano-type trend for C3H6 in ZSTU-10. The C3H6 uptake initially rose from 60.2 cm3 cm-3 to 97.3 cm3 cm-3 and then decreased to 91.2 cm3 cm-3, reaching a maximum at 298 K (Fig. 3d). In contrast, C3H8 adsorption does not reach equilibrium under the same conditions and shows an apparent increase with temperature, consistent with kinetically limited uptake. To probe the origin of this behavior, single-crystal X-ray diffraction data and in situ variable-temperature PXRD were collected at different temperatures (Supplementary Fig. 17 and Supplementary Table 1). Both analyses indicate that the framework of ZSTU-10 remains essentially rigid across the examined temperatures, and the key geometric parameters of the sieving gate (4.4 × 3.4 Å2) and diffusion channel show no discernible changes, indicating that these factors were not rationale for effect on adsorption (Supplementary Figs. 55-57). Similar temperature-dependent anomalies have been reported by Fernandez. et al56 and Zhou. et al57, leading to the inference that lower temperatures diminish the kinetic energy of guest molecules, hindering their ability to surpass the aperture energy barrier despite favorable thermodynamics58,59. Consistent with this interpretation, time-dependent adsorption isotherms demonstrated that the enhanced intrinsic kinetic energy of guest with rising temperature yield faster diffusion coefficients (Supplementary Table 6). It is suggested that the optimal configuration of the pore gate and diffusion channel collectively establish an optimal operating window around 298 K, where transport limitations are sufficiently alleviated while adsorption affinity remains high, thereby enabling simultaneous high thermodynamic and kinetic separation of C3H6/C3H8.

Host-guest structure studies
To elucidate the adsorption mechanism and host-guest interactions of C3H6 and C3H8 in ZSTU-10, we performed Grand Canonical Monte Carlo (GCMC) simulations at room temperature and 0.1 kPa, 10 kPa and 100 kPa, together with Dispersion-corrected density functional theory (DFT-D) calculations to evaluate the binding force of C3H6 molecules in ZSTU-10. At ambient temperature and 100 kPa, the density distribution maps indicate C3 molecules are preferentially located near the oxalate ligands of ZSTU-10, proving that gas molecules diffuse into the cavity parallel to the c-axis of the pore window. Compared to the C3H8 density, the simulated C3H6 density was significantly higher at 0.1 kPa. Moreover, with the pressure increases, a dense packing of C3H6 molecules exhibits minimal variation between 10 kPa and 100 kPa, consistent with the experimentally observe steep low-pressure uptake (Supplementary Fig. 58). Furthermore, GCMC simulations revealed that two C3H6 molecules were adsorbed in the central large cavity, which is consistent with the static adsorption data. DFT-D calculations were conducted to quantify the adsorbent-adsorbate binding energy in ZSTU-10 (Supplementary Fig. 59). Corroborating the GCMC results, C3H6 molecules in ZSTU-10 primarily anchor to the oxygen atoms of the oxalate ligands, forming strong C-H···O interactions (2.701-2.987 Å). Additional weaker C-H···O interactions at around 3.933 Å are formed with distal oxygen atoms. Along the b-axis direction, C3H6 molecules interact with the triazole linkers via hydrogen-bonding interactions of d(C3H6···TRZ) C-N···H at around 2.477-2.980 Å. The static binding energy of C3H6 at the binding sites was calculated to be 41.4 kJ mol-1, which is in good agreement with the experimental Qst value (45.5 kJ mol-1). In comparison, the static binding energy of C3H8 was only 13.2 kJ mol-1, revealing much weaker binding forces. As depicted in Supplementary Fig. 62, C3H6 molecules located in the middle of the pore cavity in ZSTU-11, forming multiple C-H···O interactions (2.792-3.536 Å) and intermolecular d(C3H6···TRZ) C-H···N (2.999-3.246 Å) interactions with the framework. The calculated static binding energy for C3H6 in ZSTU-11 is 42.4 kJ mol-1, while the static binding energy for C3H8 is 20.3 kJ mol-1, with the latter being higher than in ZSTU-10 (Supplementary Figs. 61-62). Moreover, electrostatic potentials (ESP) of the pore structure of ZSTU-10, ZSTU-11, and ZSTU-12 were also calculated by DFT-D calculations, and the differentiated framework energy was exhibited in Supplementary Figs. 63-65 (the corresponding energy order is ZSTU-11 > ZSTU-10 > ZSTU-12). The results reveal strong negative potentials near the oxygen atoms of oxalate ligands. Simulated results and calculated static binding energies are consistent with the experimental sorption phenomenon of ZSTU-10 and ZSTU-11.

To obtain direct structural insight into the adsorption behavior of ZSTU-10, high-resolution neutron powder diffraction (NPD) experiments were conducted to accurately establish the supramolecular binding forces between C3D6 molecules and the framework (Supplementary Fig. 11b). Two independent adsorption sites (site Ι and Ⅱ) of C3D6 molecules were identified within the pore cavity constructed by four oxalate and eight triazole ligands, as shown in Figs. 4a-b and Supplementary Fig. 60). The occupancy of two C3D6 adsorption sites was refined to be 0.133 and 0.364 at sites Ι and Ⅱ, respectively, indicating that each unit cell can accommodate two C3D6 molecules. This result corresponds to a volumetric uptake of 101.0 cm3 cm-3 (STP), which is in excellent agreement with the experimental uptake from the C3H6 isotherm (97.3 cm3 cm-3) at 298 K and 1 bar. As depicted in Fig. 4, site Ⅱ serves as the predominant sorption site and owns a higher occupancy, which was anchored by the surrounding oxalate ligands to form multiple C-D···O interactions (2.386-3.402 Å). Site Ι is located adjacent to the oxalate ligands and triazole ligands, binding to these ligands via C-D···N interactions (2.048-3.361 Å) and stronger C-D···O (2.222-3.501 Å) hydrogen bonds (Fig. 4c). In addition, a negligible framework deformation can be found when comparing the structure of activated ZSTU-10 with that of C3D6-loaded ZSTU-10, confirming the structural rigidity of ZSTU-10. These results demonstrate that the precise pore window and expansive cavity are prerequisites for achieving effective molecular sieving and high-density C3H6 packing, while the interconnected diffusion channels are essential for facilitating rapid guest transport.

Breakthrough experiments
Motivated by the superior separation capacity of ZSTU-10 in single-component adsorption/desorption performance, we further conducted binary C3H6/C3H8 (v/v=50/50) column breakthrough experiments, in which equimolar binary mixtures flowed over the sample bed of MOFs with different flow rates at 298 K (Supplementary Fig. 66). Dynamic breakthrough experiments revealed that both ZSTU-10 and ZSTU-11 are capable of separating C3H6 from an equimolar C3H6/C3H8 mixtures (Fig. 5a and Supplementary Fig. 71). However, the separation efficiency distinguishes the two materials. Notably, at a total flow rate of 3 mL min-1, the breakthrough curves for the equimolar C3H6/C3H8 mixture show that C3H8 elutes first, and the co-adsorption interval is short (4.2 min g-1). After the overlap ends, a clear time window is observed in which C3H6 is retained while C3H8 has already eluted, enabling a wide separation window with mass-normalized retention time of approximately 16.6 min g-1 for high-purity C3H6 collection (Fig. 5a). The dynamic C3H6 capacity of ZSTU-10 was calculated to be 2.76 mmol g-1 based on C3H6/C3H8 breakthrough adsorption curves, surpassing that of ZU-609 (1.64 mmol g-1)60, KAUST-7 (0.65 mmol g-1)37, Y-abtc (1.26 mmol g-1)37 and Co-gallate (0.98 mmol g-1)38 (Fig. 5b and Supplementary Fig. 67). At a higher flow rate of 5 mL min-1, ZSTU-10 maintains a limited co-adsorption interval (8.6 min g-1), whereas ZSTU-11 exhibits a substantially longer co-adsorption interval (15 min g-1) under comparable conditions (Supplementary Figs. 68 and 72). Besides, the retention time of C3H6/C3H8 for ZSTU-11 below the co-adsorption interval reveals the poor separation efficiency. The shorter overlap for ZSTU-10 indicates reduced co-elution and thus improved dynamic separation performance for equimolar C3H6/C3H8 mixtures. The excellent breakthrough performance of ZSTU-10 prompted us to explore C3H6 purity and productivity, the desorption experiments were conducted through helium gas sweeping (10 mL min-1) at 448 K (Supplementary Fig. 69). Correspondingly, the purity and productivity of the preferentially adsorbed C3H6 was 99.1% and 37.5 L kg-1 (Figs. 5e-f and Supplementary Fig. 70). These metrics exceed those of reported benchmark MOFs with sensational performance, such as for KAUST-7 (16.3 L kg-1, 90% purity )46 and Y-abtc (1.3 L kg-1, 90% purity)37 (Supplementary Table 9). Five consecutive breakthrough adsorption/desorption measurements for an equimolar C3H6/C3H8 mixture were carried out at the flow rate of 5 mL min-1. The results revealed consistent retention times, no obvious loss of capacity, and a sustained C3H6 dynamic capture at around 3.7 mmol g-1 (Fig. 5c and Supplementary Fig. 68), confirming the excellent regenerability and cycling stability of ZSTU-10. Overall, these dynamic results demonstrate the practical potential of ZSTU-10 for C3H6/C3H8 separation. Because C3H8 adsorption is strongly suppressed by molecular sieving, regeneration primarily involves desorbing C3H6 from the high-affinity sites, which can reduce unnecessary energy expenditure associated with co-adsorbed impurities.

Given the demanding conditions prevalent in practical industrial production, we investigated the stability of ZSTU-10 under a range of relevant environments. The synthesized sample was exposed to air for 15 d and immersed in water for a week. The PXRD patterns indicate that ZSTU-10 can maintain substantial structural integrity without phase change or loss of crystallinity. Stable adsorption capacities of C3H6 for ZSTU-10 can be preserved after treatment with water at different time intervals (Supplementary Fig. 19). Furthermore, this material was soaked in different chemical environments for a week, such as organic solvents (DMF, MeOH, EtOH, CH2Cl2, ACN and acetone) and acid and alkaline solutions (pH = 2, 4, 10, 12). In all cases, the samples exhibited PXRD patterns identical to the simulated one, demonstrating exceptional chemical stability (Supplementary Figs. 20-21). Five consecutive single-component adsorption-desorption isotherms were conducted at 298 K and 1 bar, which consistently showed high levels of C3H6 adsorption capacity on ZSTU-10 (Fig. 5g and Supplementary Fig. 72). Additionally, the synthesis of ZSTU-10 uses inexpensive, readily available raw materials and demonstrates potential for scalability. Combined the advantages of good stability, low production cost, and the ability to simultaneously exclude C3H8 while efficiently adsorbing C3H6 renders ZSTU-10 a promising candidate for industrial application.

Methods
Synthesis of ZSTU-10
ZnCO3 (0.627 g, 5 mmol), H2C2O4 (0.45 g, 5 mmol), and 1,2,4-triazole (TRZ, 1.727 g, 25 mmol) were added to the mixture of H2O (15 mL) and N-butyl alcohol (n-BuOH) (15 mL) in a 100 mL Teflon-lined reaction vessel. The mixed solution was stirred for an hour and reacted in an oven at 453 K for three days. After cooling to room temperature naturally, the resulting colorless crystals were collected by filtration and washed thoroughly with methanol. Finally, the product was dried in air overnight. To assess the potential for scale-up, we optimized the synthesis conditions. We confirmed that ZSTU-10 can be synthesized with high purity and crystallinity using a reduced molar ratio of 1:1:5, significantly lowering ligand consumption. Based on this optimized ratio and laboratory reagent prices, the estimated raw material cost is approximately $50.1 kg-1 (Supplementary Fig. 73), which serves as a promising baseline for future industrial economic evaluation.

Synthesis of ZSTU-11 and ZSTU-12
ZSTU-11 and ZSTU-12 were synthesized following the same procedure as ZSTU-10, except that n-BuOH was replaced by n-propyl alcohol (n-PrOH) or Isopropyl alcohol (i-PrOH), respectively.

Single-component sorption experiments
Prior to gas adsorption tests, approximately 200 mg of samples in the sample cell were activated under a dynamic vacuum at 423 K overnight to remove the guest molecules until the pressure stabilized. After each single-adsorption measurement, the sample cell was degassed at 333 K under vacuum for 0.5 h. C3H6 and C3H8 adsorption isotherms were collected from 243 K to 333 K on an automatic volumetric adsorption instrument (Micromeritics 3-Flex analyzer, 3-Flex Version 5.02). For each pressure point, an equilibrium time of 6 min was applied. Data were recorded only after a stability criterion was met: the system pressure changed by less than 0.1% over a consecutive 2 min period. The experimental adsorption-desorption temperatures were controlled by the ice bath (273 K) and a constant water bath (298 K). The Brunauer-Emmett-Teller (BET) specific surface areas were analyzed using nitrogen adsorption isotherms at 77 K. The 195 K CO2 was performed in the mixtures of dry ice and acetone. The low temperatures from 243 K to 263 K were controlled by the mixtures of dry ice, ethanol, and ethylene glycol. The data visualization uses OriginPro 2024.

Dynamic breakthrough experiments
Fixed bed breakthrough experiments were carried out in a packed stainless steel column (10 mm × 12 cm) at 298 K and 1 bar. The breakthrough column was filled with activated samples (3.6 g) at ambient conditions. A stream of Argon was introduced into the column to purge the adsorbents for 15 h at 423 K in a temperature controller of the thermostat before the breakthrough experiments. The total inlet flow rate was controlled by calibrated mass flow controllers (MFCs) and was kept constant throughout each breakthrough experiment. The breakthrough column experiments were conducted using the gas mixture of C3H6/C3H8 (v/v, 50/50) with a stable flow rate of 5 mL min-1 at 298 K, and the outgas of the column was monitored by a gas chromatograph (GC-2014C Shimadzu) equipped with a thermal conductivity detector for continuous gas analysis. When both C3H6 and C3H8 reached equilibrium, the desorption experiments were conducted through high-purity Ar (99.999%) with a flow rate of 10 mL min-1 at 298 K, and then heated up to 448 K to sweep. Five consecutive breakthrough adsorption–desorption cycles were performed to evaluate the cycling stability of ZSTU-10.

Peer review rounds
[{"round": 1, "reviewer_comments": {"reviewer_1": "1) There are many papers on the propane/propylene separation by adsorption using various adsorbents (zeolites. MOFs,\ncarbon,...) and technologies (PSA, VSA, SMB...)\nHere a list of papers not cited including a patent application\nProcédé de séparation du propylène en mélange avec du propane par adsorption en Lit Mobile Simulé en phase gaz ou\nliquide utilisant une zéolithe de type faujasite 13X comme solide adsorbant (French patent 2.903.981, application No 06\n06827, 24/07/ 2006); PCT WO 2008/012410 A! “Method of separating propylene in mixture with propane by adsorption in\nsimulated moving bed” published January 31, 2008 , US Patent Application US 2010/0069696 A1 “Process for separating\npropylene mixed with propane by adsorption in a simulated moving bed”, March 2010\nRute Seabra et al , \"Propane and Propylene separation with carbon dioxide at mild temperatures by gas-phase SMB in\nbinderfree zeolite 13X\", Ind Eng Chem Res (2023) doi.org/10.1021/acs.iecr.3c01601\nV F Martins et al , “Gas-Phase Simulated Moving Bed: Propane/Propylene Separation on 13X Zeolite”, J Chromatography A\n1423, 136-148 (2015).\nM. Campo et al , “Gas phase SMB for propane/propylene separation using enhanced 13X zeolite beads”, Adsorption. 20, 61-\n75 (2014)\nM. Campo et al , “New 13X zeolite for propylene/propane separation by VSA”, Separation and Purification Technology 103,\n60-70 (2013)\nM. Plaza et al , “Propylene/propane separation by Vacuum swing adsorption using CuBTC spheres”, Separation and\nPurification Technology 90, 109-119 (2012)\nM. G. Plaza et al , Propane/propylene separation by adsorption using shaped copper triittritrimesate MOF”, Microporous and\nMesoporous Materials 157, 101-111 (2012)\nAlexandre Ferreira et al , “Suitability of Cu-BTC extrudates for propane/propylene separation by adsorption processes”, The\nChem Eng J 167, 1-12 (2011)\nM. Granato et al , “Potential Desorbents for Propane/Propylene Separation by Gas Phase Simulated Moving Bed: A\nMolecular Simulation Study\", Ind Eng Chem Res 49 (12) 5826-5833 (2010)\nJ.Gascon et al , “Propane / Propylene separation with Li-Exchanged zeolite 13X, Chemical Engineering Journal, 160, 207-\n214 (2010)\nN. Lamia et al , \"Adsorption Equilibrium of Propane, Propylene and Isobutane on CuBTC: Experiments and Molecular\nSimulation”, Chem Eng Science 64, 3246-3259(2009)\nN. Lamia et al , “Propane / Propylene Separation by Simulated Moving Bed\nII. Measurement and Prediction of Binary Adsorption Equilibria of Propane, Propylene,Isobutane and 1-Butene on 13X\nZeolite , Sep Sci Tech, 44, 1485-1509 (2009)\nP.S. Gomes et al , “Design of a Gas Phase Simulated Moving Bed for Propane/Propylene Separation”, Chem Eng Science\n64, 1336-1357 (2009)\nN. Lamia et al , “ Equilibrium and fixed bed adsorption of 1-butene, propylene and propane over 13X zeolite pellets”, Sep Sci\nTechnology 43, 1124-1156 (2008)\nN. Lamia et al , “Propane / Propylene Separation by Simulated Moving Bed I. Adsorption of Propane, Propylene and\nIsobutane in Pellets of 13X Zeolite”, Separation Science and Technology, 42, 2539-2566 (2007)\nC. Grande et al , “Adsorption of Propane and Propylene in Zeolite 4A Honeycomb Monolith”, Chem. Eng. Sci , 61, 3053-\n3067(2006)\nC. Grande et al , \"Propane - Propylene Separation by Pressure Swing Adsorption Using Zeolite 4A\", Ind. Eng. Chem. Res.\n44, 8815-8829 (2005)\nC.Grande et al , “Adsorption kinetics of propane and propylene in zeolite 4A”, Chem Eng Res Dev 82 (A12),1604-1612\n(2004)\nC. A. Grande et al , “Adsorption of binary mixtures of propane-propylene in Carbon Molecular Sieve 4A”, Ind Eng Chem Res\n43, 8057-8065 (2004)\nC. Grande et al , “Crystal Size Effect in Vacuum Pressure Swing Adsorption for Propane / Propylene Separation”, Ind Eng\nChem Res 43, 7557-7565(2004)\nC. Grande et al , “Propane-propylene binary adsorption on zeolite 4A”, Adsorption 9, 321-329 (2003)\nCarlos Grande et al , “Adsorption of propane and propylene in pellets and crystals of 5A zeolite”, IECR , 41(1) 85-92 (2002)\nF.A. da Silva et al, “Vacuum swing adsorption for Propylene/Propane separation with 4A zeolite pellets”, Ind Eng Chem Res\n40(24) 5758-5774(2001)\nF.A. da Silva et al , “Propylene/Propane separation by VSA using commercial 13X zeolite pellets”, AIChEJ 47(2) 341-\n357(2001)\nF.A.da Silva et al ,”Adsorption equilibria and kinetics for propylene and propane over 13X and 4A zeolite pellets”, Ind Eng\nChem Res 38(5) 2051-2057 (1999)\n2) How long it was the equilibration time in equilibrium experiments with propane?\n3) I missed information on particle size and precise dimensions of the column in breakthrough experiments\n4) I found very strange statements like \"retention time of approximately 16.6 279 min g-1 \", \"eluted out at 20.8 min g-1,\".\nThese are not units of time\n5) Why do you fit equilibrium data at some point with dual-site Langmuir Freundlich (Supplementary note 1) and later in\nSupplementary note 3 with Langmuir?\n6) Supplementary Figure 67\nThe calculations of adsorbed amount as shown are not correct. Mass balances should be done from figures of molar flow\nversus time and not concentrations. Otherwise I need volumetric flowrate versus time also.", "reviewer_2": "This work by Wang et al. reported three isoreticular ultramicroporous metal-organic frameworks (ZSTU-10, ZSTU-11, and\nZSTU-12) for the selective molecular sieving of C3H6 from binary C3H6/C3H8 mixtures. Their results revealed that n-\nbutanol, as structure-directing agents constructed optimal sieving gates that efficiently distinguished C3H6 while fully\nexcluding C3H8. Simultaneously, it shaped the diffusion channels and central pore cavities to achieve exceptional C3H6\nuptake and a thermodynamic-kinetics equilibrium separation. Detailed gas adsorption isotherms, dynamic breakthrough\nexperiments and gas loaded single-crystal X-ray diffraction fully substantiated these findings. Moreover, the authors\ninverstigated these MOFs under different conditions and comfirmed its viability and effectiveness. Therefore, the overall\nnovelty of this work is sufficient and the olefin/alkane separation is very pivotal in industry. I can recommend this for\npublication in Nature Communication after revisions. Here are some sepcific comments.\n1. Based on its molecular structure and static adsorption isotherms, ZSTU-10 exhibits exceptionally high C3H6/C3H8\nselectivity. What advantages does it offer compared to previously reported sieving materials?\n2. The dmc topology reported in this work is not commoly encountered, and a more comprehensive literature-based\ndiscussion of the topological configuration of ZSTU-10 would greatly help the article readers.\n3. The author presents adsorption data in units of cm3 cm-3 (volumetric) rather than the conventional units of cm3 g-1 and\nmmol g-1 (gravimetric). Colud the authors clarify the necessity for using volumetric adsorption and discuss its advantages in\nthis specific context compared to gravimetric units?\n4. In the synthesis and characterization section, there is an inconsistency between the manuscript and the supplementary\ninformation regarding the reported cavity size. The manuscirpt states the dimension as 8.5 × 6.3 × 6.5 Å3, whereas the\nsupporting information lists it as 8.5 × 6.0 × 6.2 Å3, so this mistake should be corrected for consistency.\n5. In Fig. 3d, the C3H6/C3H8 uptake ratio is not presemt in the figure; instead, the data likely represent the C3H6 uptake at\n0.1 bar from 243 K to 333 K.\n6. In Supplementary Figure 72, the components in the breakthrough curves are mislabeled, because the more strongly\nadsorbed component of C3H6 should not be eluted first.\n7. The manuscript conatins several grammatical and typographical erroes that require attention. For example:\nPage 7, the term “Qst” should be defined upon its first introduction, which occurs in the preceding sentence.\nPage 9, the multiple C-H···O interactions in ZSTU-11 is given as 2.793-3.536 Å but should be corrected to 2.792-3.536 Å.\nIn Fig. 5d, the chemical formulas “C3H6” and “C3H8” should be formatted with subscripts as “C3H6” and “C3H8”.\n8. The raw materials used by the author are very cheap. Has large-scale synthesis and economic evaluation been\nconducted? This is very meaningful for practical applications.", "reviewer_3": "The authors have synthesized a MOF series, featuring central pore cages with sieving gates apertures connected to fast\ndiffusion channels, using alcohol structure directing agents. The obtained ZSTU-10 MOF achieved a good separation of\npropylene from propane via a thermodynamic-kinetics equilibrium optimization in molecular sieving. The study is\nmeaningful, addressing the key bottleneck of thermodynamic-kinetic trade-off. And the resultant propylene uptake and\ndiffusion coefficient have exceeded those of the MOFs with similar cavity-channel microstructures. The manuscript is well\nwritten, the experimental evidences are self-consistent. But still, some key questions need to be answered before it is\npublication. The detailed comments are listed as below.\n1. The authors addressed the structure-directing agents of the three alcohols to template the featured pore structures of\nZSTU-10, 11 and 12, they only provided the final results of the bond angles and lengths. There was a lack of a discussion of\ntheir roles on the subtle differences of the isoreticular micropores shown in Figure 1a. Besides, have all the solvent\nmolecules been removed from the cavities to conduct the subsequent characterizations? Will the pore apertures maintain\nafter thoroughly removing all the water and alcohol solvent molecules at elevated temperatures? It is surprising that ZSTU-\n12 displayed a negligible N2 uptake compared to ZSTU-10 and 11. Overall, the authors need to carefully validate whether\nthe three isoreticular structures are de facto one accompanied with two intermediate state structures.\n2. The C3H6 uptake for ZSTU-10 at 0.1 bar has approached to the saturated adsorption capacity (97.7 cm3 cm-3) at 1 bar.\nThe value has far surpassed other MOF sorption performances. Please present a discussion on this phenomenon.\n3. The 50/50 propylene/propane co-adsorption analysis should be supplemented.\n4. There are many clerical errors. For example, there is no Fig. 3i in the main text, it should be Fig. 3f.\n5. Fig. 5d, why is there a peak signal for C3H6 desorption? And how does the ZSTU perform for a consecutive breakthrough\ncycles, like four or five times. Please present the breakthrough curves."}, "author_response": "Reply to Reviewers’ Comments to Author: Referee 1\n1. There are many papers on the propane/propylene separation by adsorption using\nvarious adsorbents (zeolites. MOFs, carbon,...) and technologies (PSA, VSA, SMB...)\nHere a list of papers not cited including a patent application.\nProcédé de séparation du propylène en mélange avec du propane par adsorption en Lit\nMobile Simulé en phase gaz ou liquide utilisant une zéolithe de type faujasite 13X\ncomme solide adsorbant (French patent 2.903.981, application No 06 06827, 24/07/\n2006); PCT WO 2008/012410 A! “Method of separating propylene in mixture with\npropane by adsorption in simulated moving bed” published January 31, 2008 , US\nPatent Application US 2010/0069696 A1 “Process for separating propylene mixed with\npropane by adsorption in a simulated moving bed”, March 2010\nRute Seabra et al, “Propane and Propylene separation with carbon dioxide at mild\ntemperatures by gas-phase SMB in binderfree zeolite 13X”, Ind Eng Chem Res (2023)\ndoi.org/10.1021/acs.iecr.3c01601\nV F Martins et al, “Gas-Phase Simulated Moving Bed: Propane/Propylene Separation\non 13X Zeolite”, J Chromatography A 1423, 136-148 (2015).\nM. Campo et al, “Gas phase SMB for propane/propylene separation using enhanced\n13X zeolite beads”, Adsorption. 20, 61-75 (2014)\nM. Campo et al, “New 13X zeolite for propylene/propane separation by VSA”,\nSeparation and Purification Technology 103, 60-70 (2013)\nM. Plaza et al, “Propylene/propane separation by Vacuum swing adsorption using\nCuBTC spheres”, Separation and Purification Technology 90, 109-119 (2012)\nM. G. Plaza et al, “Propane/propylene separation by adsorption using shaped copper\ntriittritrimesate MOF”, Microporous and Mesoporous Materials 157, 101-111 (2012)\nAlexandre Ferreira et al, “Suitability of Cu-BTC extrudates for propane/propylene\nseparation by adsorption processes”, The Chem Eng J 167, 1-12 (2011)\nM. Granato et al, “Potential Desorbents for Propane/Propylene Separation by Gas Phase\nSimulated Moving Bed: A Molecular Simulation Study\", Ind Eng Chem Res 49 (12)\n5826-5833 (2010)\nJ.Gascon et al, “Propane/Propylene separation with Li-Exchanged zeolite 13X,\nChemical Engineering Journal, 160, 207-214 (2010)\nN. Lamia et al, “Adsorption Equilibrium of Propane, Propylene and Isobutane on\nCuBTC: Experiments and Molecular Simulation”, Chem Eng Science 64, 3246-\n3259(2009)\nN. Lamia et al, “Propane/Propylene Separation by Simulated Moving Bed\nII. Measurement and Prediction of Binary Adsorption Equilibria of Propane,\nPropylene,Isobutane and 1-Butene on 13X Zeolite , Sep Sci Tech, 44, 1485-1509 (2009)\nP.S. Gomes et al, “Design of a Gas Phase Simulated Moving Bed for Propane/Propylene\nSeparation”, Chem Eng Science 64, 1336-1357 (2009)\nN. Lamia et al, “Equilibrium and fixed bed adsorption of 1-butene, propylene and\npropane over 13X zeolite pellets”, Sep Sci Technology 43, 1124-1156 (2008)\nN. Lamia et al, “Propane/Propylene Separation by Simulated Moving Bed I. Adsorption\nof Propane, Propylene and Isobutane in Pellets of 13X Zeolite”, Separation Science and\nTechnology, 42, 2539-2566 (2007)\nC. Grande et al, “Adsorption of Propane and Propylene in Zeolite 4A Honeycomb\nMonolith”, Chem. Eng. Sci , 61, 3053-3067(2006)\nC. Grande et al, “Propane - Propylene Separation by Pressure Swing Adsorption Using\nZeolite 4A”, Ind. Eng. Chem. Res. 44, 8815-8829 (2005)\nC.Grande et al, “Adsorption kinetics of propane and propylene in zeolite 4A”, Chem\nEng Res Dev 82 (A12),1604-1612 (2004)\nC. A. Grande et al, “Adsorption of binary mixtures of propane-propylene in Carbon\nMolecular Sieve 4A”, Ind Eng Chem Res 43, 8057-8065 (2004)\nC. Grande et al, “Crystal Size Effect in Vacuum Pressure Swing Adsorption for Propane\n/ Propylene Separation”, Ind Eng Chem Res 43, 7557-7565(2004)\nC. Grande et al, “Propane-propylene binary adsorption on zeolite 4A”, Adsorption 9,\n321-329 (2003)\nCarlos Grande et al, “Adsorption of propane and propylene in pellets and crystals of 5A\nzeolite”, IECR , 41(1) 85-92 (2002)\nF.A. da Silva et al, “Vacuum swing adsorption for Propylene/Propane separation with\n4A zeolite pellets”, Ind Eng Chem Res 40(24) 5758-5774(2001)\nF.A. da Silva et al, “Propylene/Propane separation by VSA using commercial 13X\nzeolite pellets”, AIChEJ 47(2) 341-357(2001)\nF.A.da Silva et al, “Adsorption equilibria and kinetics for propylene and propane over\n13X and 4A zeolite pellets”, Ind Eng Chem Res 38(5) 2051-2057 (1999).\nResponse: We sincerely thank the reviewer for providing this comprehensive and\nvaluable list of literature, which highlights many significant contributions to the field\nof propane/propylene separation by adsorption. We have carefully examined all the\nsuggested references. Following the editor’s guidance, we have strategically\nincorporated citations where they are most relevant to contextualize and strengthen our\nnarrative. Specifically, we have added references on well-known adsorbents such as\nzeolite 13X and zeolite 5A in the introduction. This allows us to properly establish the\nperformance benchmarks and the challenges in the field, and to clearly contrast the\nseparation metrics of ZSTU-10 with those of these classic materials, thereby offering\nreaders with a direct and quantitative perspective on the progress achieved. By\nintegrating these references in this focused manner, we provide a more robust and\naccurate background for our study while maintaining emphasis on our novel findings.\nWe thank the reviewer again for this constructive suggestion.\nModifications:\nManuscript: Page 2 and 17\nTherefore, it is imperative to develop alternative separation technologies with lower\nenergy input and reduced capital cost. Porous materials including zeolites10-16, activated\ncarbons17,18, and metal-organic frameworks (MOFs)19-21 have garnered considerable\nattention as non-thermal separation platforms, offering the potential to markedly reduce\nenergy consumption relative to cryogenic distillation.\n12. Grande, C. A. et al. Adsorption of propane and propylene in zeolite 4A honeycomb\nmonolith. Chem. Eng. Sci. 61, 3053-3067 (2006).\n13. Grande, C. A. et al. Propane/propylene separation by pressure swing adsorption\nusing zeolite 4A. Ind. Eng. Chem. Res. 44, 8815-8829 (2005).\n14. Grande, C. A. et al. Adsorption kinetics of propane and propylene in zeolite 4A.\nChem. Eng. Res. Des. 82, 1604-1612 (2004).\n15. Grande, C. A. et al. Adsorption of binary mixtures of propane-propylene in carbon\nmolecular sieve 4A. Ind. Eng. Chem. Res. 43, 8057-8065 (2004).\n16. Grande; C. A. et al. Crystal size effect in vacuum pressure-swing adsorption for\npropane/propylene separation. Ing. Eng. Chem. Res. 43, 7557-7565 (2004).\nSupplementary Information: Page 71-72, and 74\nSupplementary Table 11. The C H uptake at 0.1 bar, and C H and C H uptake\n3 6 3 6 3 8\ncapacity, with the calculated uptake ratio, and the IAST selectivity of C H /C H\n3 6 3 8\nmixtures (v/v = 50/50), and the calculated packing density based on pore volume.\nC3H6 uptake C3H6 C3H8 Uptake IAST Packing\nMaterials Ref\nat 0.1 bara uptakeb uptakec ratio selectivity densityd\nThis\nZSTU-10 92.5 97.7 5.28 24.5 7886.7 633\nwork\nThis\nZSTU-11 88.6 93.6 55.4 1.69 50.7 450\nwork\nHIAM-301 69.4 92.7 8.8 10.5 >150 510 13\nJNU-3a 18.7 87.5 70.7 1.24 15.6 404 14\nZU-609 10.8 73.1 2.54 28 - - 15\nNTU-68a 52.6 70.1 9.9 7.1 2030 566 16\nDL-mal-MOF 46.2 65.7 38.9 1.6 - 620 3\nY-abtc 35.0 63.0 8.9 7.1 >107 462 17\nCo-gallate 17.9 66.6 5.2 11.2 333 330 18\nKAUST-7 10.1 61.9 5.42 17.3 6540 623 19\nNTU-85-WNT 15.1 20.9 0.13 161 1570 265 20\nHOF-FJU-1 50.9 57.9 54.4 1.1 14.4 575 21\nMAF-23 67.0 69.9 69.8 1.0 3.2 333 4\nMAF-23-O 40.4 46.5 39 1.2 8.8 318 4\nCo2(dobdc) - 192 141 1.4 46 604 5\nFe2(dobdc) - 174 135.9 1.1 15 548 22\nNi2(dobdc) - 131 107 1.2 12 376 5\nMg2(dobdc) 144.8 171 144 1.2 7.5 553 5\nCo2(m-dobdc) 29.9 200 160 1.3 38 523 23\nNi2(m-dobdc) 38.2 164.2 163 1.2 35 - 23\n13X zeolite - 69.1 52.7 1.3 8.2 - 24-32\nCu-BTCe 96.8 126.3 107.2 1.2 - - 33-36\nZeolite 5Ae 96.7 124.5 108.9 1.1 1.35 310 37\na, b, and c The unit C3H6 uptake was cm3 cm-3. d The unit of packing density was g L-1. e The gas adsorption data were\nmeasured at 323 K.\n25. Seabra, R. et al. Propane and propylene separation with carbon dioxide at mild\ntemperatures by gas-phase simulated moving bed in binderfree zeolite 13X. Ind. Eng.\nChem. Res. 62, 12600-12612 (2023).\n26. Campo, M. C. et al. Gas phase SMB for propane/propylene separation using\nenhanced 13X zeolite beads. Adsorption 20, 61-75 (2013).\n27. Campo, M. C. et al. New 13X zeolite for propylene/propane separation by vacuum\nswing adsorption. Sep. Purif. Technol. 103, 60-70 (2013).\n28. Da Silva, F. A. et al. Propylenepropane separation by vacuum swing adsorption\nusing 13X zeolite. AlChE J. 47, 341-357 (2001).\n29. Lamia, N. et al. Propane/propylene separation by simulated moving bed Ⅱ.\nMeasurement and prediction of binary adsorption equilibria of propane, propylene,\nisobutane, and 1-butene on 13X zeolite. Sep. Sci. Technol. 44, 1485-1509 (2009).\n30. Sá Gomes, P. et al. Design of a gas phase simulated moving bed for\npropane/propylene separation. Chem. Eng. Sci. 64, 1336-1357 (2009).\n31. Lamia, N. et al. Equilibrium and fixed bed adsorption of 1‐butene, propylene and\npropane over 13X zeolite pellets. Sep. Sci. Technol. 43, 1124-1156 (2008).\n32. Lamia, N. et al. Propane/propylene separation by simulated moving bed I. Adsorption\nof propane, propylene and isobutane in pellets of 13X zeolite. Sep. Sci.\nTechnol. 42, 2539-2566 (2007).\n33. Ferreira, A. F. P. et al. Suitability of Cu-BTC extrudates for propane–propylene\nseparation by adsorption processes. Chem. Eng. J. 167, 1-12 (2011).\n34. Lamia, N. et al. Adsorption of propane, propylene and isobutane on a metal–\norganic framework: Molecular simulation and experiment. Chem. Eng. Sci. 64, 3246-\n3259 (2009).\n35. Plaza, M. G. et al. Propylene/propane separation by vacuum swing adsorption\nusing Cu-BTC spheres. Sep. Purif. Technol. 90, 109-119 (2012).\n36. Plaza, M. G. et al. Propane/propylene separation by adsorption using shaped copper\ntrimesate MOF. Micropor. Mesopor. Mater. 157, 101-111 (2012).\n37. Grande, C. A. et al. Adsorption of propane and propylene in pellets and crystals of\n5A zeolite. Ind. Eng. Chem. Res. 41, 85-92 (2002).\n2. How long it was the equilibration time in equilibrium experiments with propane?\nResponse: We appreciate the reviewer for raising this critical point regarding the\nexperimental rigor. For the single-component adsorption isotherms, the equilibration\ninterval was controlled by a strict pressure stability criterion. specifically, the\ninstrument was set to record a data point only after the pressure change was less than\n0.1% over a consecutive 2-minute period, with a maximum allowance of 6 minutes per\npoint. It is worth noting that for ZSTU-10, due to the effective molecular sieving (size\nexclusion) of propane (C H ), the gas uptake was negligible. Consequently, the system\n3 8\npressure stabilized rapidly after each dose, satisfying the stability criterion well within\nthe set timeframe. We have now explicitly included these parameter details in the\nMethods section to ensure the reproducibility of our data.\nModifications:\nManuscript: Page 15 (Methods section)\nFor each pressure point, an equilibrium time of 6 min was applied. Data were recorded\nonly after a stability criterion was met: the system pressure changed by less than 0.1%\nover a consecutive 2 min period.\n3. I missed information on particle size and precise dimensions of the column in\nbreakthrough experiments.\nResponse: Thank you for pointing out the missing experimental details that are\nessential for reproducibility. We apologize that these parameters were not clearly\nreported in the original submission. In our breakthrough experiments, the adsorbents\nwere used as as-synthesized powders (without pelletization). The average particle sizes\nwere determined from SEM image statistics and are summarized in Supplementary\nTable 6 (mean crystal size: 14.3 μm for ZSTU-10 and 16.5 μm for ZSTU-11). We have\nalso clarified the breakthrough column specifications and bed preparation. The column\nused for the dynamic breakthrough tests has an inner diameter of 10 mm and a length\nof 12 cm. The column was packed with a known mass of adsorbent and tapped gently\nto ensure uniform packing. All relevant parameters for the breakthrough setup (column\ndimensions, adsorbent mass, and operating conditions) are now explicitly provided in\nthe Methods (Dynamic breakthrough experiments) and cross-referenced in the\nSupplementary Information.\nModifications:\nSupplementary Information: Page 68\nSupplementary Table 6. The diffusion coefficient for ZSTU-10 and ZSTU-11, and the\naverage particle size are obtained from SEM analysis.\n4. I found very strange statements like “retention time of approximately 16.6 min g-\n1”, “eluted out at 20.8 min g-1”. These are not units of time.\nResponse: We agree with the reviewer that the unit min g-1 is dimensionally distinct\nfrom time, and the original phrasing was imprecise. We employed this mass-normalized\nmetric to facilitate direct comparisons of column efficiency across experiments with\ndifferent adsorbent packing weights, which is a common practice in adsorption\nengineering. To address the reviewer’s concern and ensure scientific rigor, we have\nrenamed this parameter as mass-normalized breakthrough time throughout the\nmanuscript. We have revised both the main text (Page 11) and the caption of Fig. 5 to\nexplicitly define this unit, thereby avoiding any dimensional ambiguity.\nModifications:\nManuscript: Page 13\nFig. 5. Dynamic breakthrough experiments of ZSTU-10. For calculation and\ncomparative analysis, all breakthrough time parameters are reported as mass-\nnormalized breakthrough time (min g-1). (a) Dynamic column curves in ZSTU-10 for\nC H /C H (50/50) with a flow rate of 3 mL min-1. (b) Comparison of the dynamic C H\n3 6 3 8 3 6\nuptake of ZSTU-10 with other reported C H /C H sieving materials. (c) Dynamic\n3 6 3 8\nuptake of cyclic tests on ZSTU-10 for C H /C H mixtures. (d) Dynamic adsorption\n3 6 3 8\nbreakthrough curves at a flow rate of 5 mL min-1, followed by desorption curves under\nArgon gas with a sweeping flow rate of 10.0 mL min-1. The desorption occurs in two\nstages: first purging at 298 K, followed by purging at 448 K. (e) Comparison of C H\n3 6\nproductivity with well-known MOFs. (f) Comparison of C H purity among other\n3 6\nfamous sieving MOFs. (g) Cycling adsorption-desorption curves on ZSTU-10 at 298 K\nand 1 bar.\n5. Why do you fit equilibrium data at some point with dual-site Langmuir Freundlich\n(Supplementary note 1) and later in Supplementary note 3 with Langmuir?\nResponse: We appreciate the reviewer’s scrutiny regarding the modeling of\nadsorption data. We employed these two models for distinct and complementary\nanalytical objectives, which is a standard practice in gas separation studies:\n(1) For IAST Calculations (Supplementary Note 1): The Dual-Site Langmuir-\nFreundlich (DSLF) model was selected because it provides a highly accurate\nmathematical fit over the entire pressure range (from 0 to 1 bar). IAST calculations are\nsensitive to the fitting precision, especially for isotherms with heterogeneity or\ninflection points. The DSLF model, with its additional parameters, captures these\nfeatures better than a simple Langmuir model, ensuring reliable mixture selectivity\npredictions.\n(2) For Henry’s Constants (Supplementary Note 3): The Langmuir model was\nspecifically applied to fit the low-pressure region (infinite dilution limit). In this regime,\nadsorption behavior is dominated by adsorbent-adsorbate interactions rather than\nadsorbate-adsorbate interactions. The Langmuir equation allows for the direct and\nrobust extraction of the Henry’s constant from the initial slope (affinity parameter b),\navoiding the potential over-parameterization issues of DSLF in the linear region.\nWe have clarified and revised this distinction in the Supplementary Information to\navoid confusion.\nModifications:\nSupplementary Information: Page 4 and 73\nPage 4: To determine the Henry’s constants and evaluate the intrinsic thermodynamic\naffinity at the infinite dilution limit, the experimentally collected isotherms of C H and\n3 6\nC H at 298 K on ZSTU-10 and ZSTU-11 were fitted using the single-site Langmuir\n3 8\nequation (focusing on the low-pressure region), as distinct from the DSLF model used\nfor full-range IAST fitting3.\nPage 73: 3. Zheng, F. et al. Shell‐like xenon nano‐traps within angular anion‐pillared\nlayered porous materials for boosting Xe/Kr separation. Angew. Chem. Int. Ed. 61\n(2022).\n6. Supplementary Figure 67\nThe calculations of adsorbed amount as shown are not correct. Mass balances should\nbe done from figures of molar flow versus time and not concentrations. Otherwise, I\nneed volumetric flowrate versus time also.\nResponse: We sincerely thank the reviewer for this critical comment, which allows us\nto clarify the mass balance calculation in greater detail. We fully agree that directly\nintegrating the molar flow rates is a fundamental and rigorous approach.\nIn our experiments, the total inlet volumetric flow rate (V) was maintained\nconstant by mass flow controllers (MFCs), and the inlet composition was fixed at 50/50\n(v/v). Therefore, the inlet molar flow rate of the target component (i) was constant\nthroughout the experiment:\n𝐶 𝑉\n𝑖𝑛,𝑖\nṅ =\n𝑖𝑛,𝑖 22.4\nWhere C = 0.5 (molar/volume fraction), V is the volumetric feed flow rate (cm3\nin,i\nmin-1).\nAt the outlet, we monitored the normalized concentration C/C (or F/F ) in real\n0 0\ntime, Thus, the outlet molar flow rate of component i at any time t is:\n𝐶\nṅ (𝑡) = ṅ ×[ (𝑡)]\n𝑜𝑢𝑡,𝑖 𝑖𝑛,𝑖 𝐶\nfrom 0-t:\n1 𝑡 1 𝑡 𝐶\n𝑞 = × ∫ [ṅ −ṅ (𝑡)]𝑑𝑡 = × ∫ ṅ ×[1− (𝑡)]𝑑𝑡\n𝑖 𝑚 𝑖𝑛,𝑖 𝑜𝑢𝑡,𝑖 𝑚 𝑖𝑛,𝑖 𝐶\n0 0 0\nWhere q is the equilibrium adsorption capacity of gas i (mmol g-1), t is the\ni\nadsorption time.\nSubstituting the expression for ṅ yields the equation we used:\n𝑖𝑛,𝑖\n𝐶 𝑉 𝑡 𝐹\n𝑖,𝑖𝑛𝑙𝑒𝑡\n𝑞 = × ∫ (1− )𝑑𝑡\n𝑖 22.4 × 𝑚 𝐹\n0 0\nWhere q is the equilibrium adsorption capacity of gas i (mmol g-1), C is the\ni i, inlet\nfeed gas molar/volume fraction, V is the volumetric feed flow rate (cm3 min-1), t is the\nadsorption time (min), F and F are the inlet and outlet gas molar flow rates, and m is\n0\nthe mass of the adsorbent (g).\nThis method is the well-established standard for evaluating MOF adsorbents, as\nutilized in recent authoritative studies (Nature 2021, 595, 542-548; Nature Chemistry\n2025, 17, 141-147). We have provided the plot of molar flow rate vs. time in\nSupplementary Figure 67. We hope these clarifications and additional data satisfactorily\naddress the reviewer’s concern.\nModifications:\nManuscript: Page 16\nThe total inlet flow rate was controlled by calibrated mass flow controllers (MFCs) and\nwas kept constant throughout each breakthrough experiment.\nSupplementary Information: Page 6 and 61\nPage 6: Total flow rate was recorded by the mass flow controllers (MFCs) and remained\nconstant within ± 0.2% during each run.\nPage 61:\nSupplementary Figure 67. Equivalence verification of mass balance calculations\nusing molar flow rates and normalized concentrations. (a) Real-time molar flow rates\nof C H and C H during the breakthrough process on ZSTU-10. (b) Calculation of\n3 8 3 6\nC H adsorption capacity by integrating the molar flow rate curve: the yellow area\n3 6\nrepresents ∫\n𝑡2[𝑛\n−𝑛 (𝑡)]𝑑𝑡. (c) Calculation based on the normalized\n𝑡1 𝑖𝑛,𝑖 𝑜𝑢𝑡,𝑖\nbreakthrough curve (C/C 0 ): the yellow area represents 𝑛 𝑖𝑛,𝑖 ∫ 𝑡 𝑡 1 2[1− 𝐶 𝐶 0 (𝑡)]𝑑𝑡. Due to\nlimited testing conditions, the comparison between dynamic and static capacities serves\nas a reliable metric for understanding co-adsorption. the integration of the C H\n3 6\nbreakthrough curve initially yielded an apparent dynamic capacity of 3.72 mmol g-1\n(the calculated area 0-t ). The discrepancy between this value and the static equilibrium\n2\ncapacity is attributed to the co-adsorption of C H within the adsorbent bed during the\n3 8\ninitial stages of the breakthrough process. After deducting co-adsorbed interval of 8.6\nmin g-1 of C H /C H co-adsorption, the calculated dynamic adsorption capacity for\n3 6 3 8\nC H is as follows: the flow rate of C H : q = 2.5 mL min-1 = 0.1116 mmol min-1,\n3 6 3 6\nbetween the breakthrough point t -t : the captured amount of C H : Q =\n1 2 3 6\n∫ 𝑡 𝑡 1 2[𝐶 𝑖 0 −𝐶 𝑖 (𝑡)]𝑑𝑡 , so t 1 -t 2 area above the entire breakthrough curves gave the\ncomparatively high loading of ZSTU-10 to be 2.76 mmol g-1, corresponding to the area:\n24.732.\nReviewer: #2\nReply to Reviewers’ Comments to Author: Referee 2\nThis work by Wang et al. reported three isoreticular ultramicroporous metal-organic\nframeworks (ZSTU-10, ZSTU-11, and ZSTU-12) for the selective molecular sieving of\nC H from binary C H /C H mixtures. Their results revealed that n-butanol, as\n3 6 3 6 3 8\nstructure-directing agents constructed optimal sieving gates that efficiently\ndistinguished C H while fully excluding C H . Simultaneously, it shaped the diffusion\n3 6 3 8\nchannels and central pore cavities to achieve exceptional C H uptake and a\n3 6\nthermodynamic-kinetics equilibrium separation. Detailed gas adsorption isotherms,\ndynamic breakthrough experiments and gas loaded single-crystal X-ray diffraction fully\nsubstantiated these findings. Moreover, the authors investigated these MOFs under\ndifferent conditions and confirmed its viability and effectiveness. Therefore, the overall\nnovelty of this work is sufficient and the olefin/alkane separation is very pivotal in\nindustry. I can recommend this for publication in Nature Communication after revisions.\nHere are some specific comments.\nResponse: We thank the reviewer for the constructive and encouraging assessment of\nour work. We are pleased that the reviewer finds the overall novelty and industrial\nrelevance of the olefin/alkane separation problem compelling. We have carefully\nconsidered all comments and have revised the manuscript and Supporting Information\naccordingly. The key revisions include improved benchmarking against prior sieving\nmaterials, expanded structural/topological discussion, clarification of adsorption\nmetrics and units, and correction of clerical issues as detailed below.\n1. Based on its molecular structure and static adsorption isotherms, ZSTU-10 exhibits\nexceptionally high C H /C H selectivity. What advantages does it offer compared to\n3 6 3 8\npreviously reported sieving materials?\nResponse: We are very grateful to the reviewer for this constructive question. While\nmany reported molecular sieves excel in selectivity, they often suffer from limited\nadsorption capacity or slow diffusion kinetics (the “permeability-selectivity” trade-off).\nThe distinct advantage of ZSTU-10 is that it simultaneously achieves ultra-high\nvolumetric capacity and rapid kinetics without compromising selectivity.\nSpecifically, compared to benchmark sieving materials (e.g., KAUST-7, Co-gallate),\nZSTU-10 offers three quantitative advantages:\n(1) Superior Kinetics: Thanks to the interconnected diffusion channels, the\ndiffusion coefficient of C H in ZSTU-10 (4.29×10-9 cm2 s-1) is two orders of magnitude\n3 6\nhigher than that of KAUST-7 (9.49×10-11 cm2 s-1), ensuring faster adsorption/desorption\ncycles.\n(2) High Volumetric Capacity: ZSTU-10 exhibits a saturated C H uptake of 97.7\n3 6\ncm3 cm-3, which surpasses most rigid sieving MOFs (e.g., ZU-609 at 73.1 cm3 cm-3).\nThis high packing density is crucial for maximizing the efficiency of fixed-bed\nindustrial columns.\n(3) High Productivity: As a result of the above two factors, ZSTU-10 delivers a\nhigh polymer-grade C H productivity of 37.5 L kg-1 in breakthrough experiments,\n3 6\noutperforming Y-abtc (1.3 L kg-1) and KAUST-7 (16.3 L kg-1).\nThe detailed comparative discussions and performance comparison figure are\npresented in Fig. 3c and 3f and Supplementary Tables 9 and 11 in the manuscript and\nSupplementary Information to visualize these advantages.\nModifications:\nManuscript: Page 7, 9\nPage 7: ZSTU-10 achieved a significant C H volumetric uptake of 92.5 cm3 cm-3 (57.0\n3 6\ncm3 g-1) at 0.1 bar and 298 K and reached a plateau at higher pressures. This\nexceptionally high low-pressure uptake is attributed to the synergistic effect of strong\nbinding sites within the central cavity and rapid transport through diffusion channels,\nwhich was a common adsorption phenomenon observed in advanced adsorbents\ndesigned for high-affinity gas capture44. At 298 K and 1 bar, The C H adsorption\n3 6\ncapacity reaches 97.7 cm3 cm-3 (60.9 cm3 g-1), reflecting its superior packing efficiency.\nThe excellent C H uptake of ZSTU-10 surpasses many benchmark sieving materials,\n3 6\nsuch as ZU-609 (73.1/10.8 cm3 cm-3)45, Y-abtc (63/35 cm3 cm-3)37, Co-gallate\n(66.6/17.9 cm3 cm-3)38, JNU-3a (87.5/18.7 cm3 cm-3)35, KAUST-7 (61.9/10.1 cm3 cm-\n3)45-48 at 1 bar and 0.1 bar (Fig. 3c and Supplementary Table 11).\nPage 9: To further quantify this distinction, the calculated diffusion coefficient of C H\n3 6\nin ZSTU-10 was 4.29 × 10-9 cm2 s-1 at 298 K and 1 bar. This value is comparable to\nZU-609 (1.36 × 10-9 cm2 s-1), and two orders of magnitude higher than other leading\nsieving materials such as Co-gallate (6.47 × 10-11 cm2 s-1), and KAUST-7 (9.49 × 10-11\ncm2 s-1) (Fig. 3f and Supplementary Fig. 9 and Figs. 53-54 and Supplementary Table\n6)50.\n2. The dmc topology reported in this work is not commonly encountered, and a more\ncomprehensive literature-based discussion of the topological configuration of ZSTU-\n10 would greatly help the article readers.\nResponse: We appreciate the reviewer’s suggestion to provide more context on the\ntopological configuration. The dmc topology of ZSTU-10 was confirmed via standard\nanalysis using ToposPro software, where the metal clusters and organic linkers are\nsimplified as connected nodes. Crucially, as the reviewer noted, this topology is\nrelatively rare but highly significant. It is constructed from 2D [Zn(TRZ)] layers\npillared by oxalate ligands, forming a robust 3D network. This configuration is\nisostructural to the renowned CALF-20 framework (a benchmark material for industrial\nCO capture), which shares the same underlying topological net. This structural kinship\n2\nexplains the excellent framework rigidity and the unique 3D channel system observed\nin ZSTU-10. In the manuscript, we have expanded the structural discussion to explicitly\nreference this relationship with CALF-20, helping readers better situate ZSTU-10\nwithin this important structural family.\nModifications:\nManuscript: Page 4 and 18\nPage 4: The planar conjugation of triazoles facilitates their preferential coordination\nwith Zn, forming two-dimensional 2D layered [Zn(TRZ)] , which are subsequently\nn\npillared by oxalate to create a three-dimensional (3D) dmc topology (Supplementary\nFig. 1), which is isostructural to the benchmark CALF-20 framework known for its high\nstability41.\nPage 18: 43. Oktavian, R. et al. Gas adsorption and framework flexibility of CALF-20\nexplored via experiments and simulations. Nat. Commun. 15, 3898 (2024).\n3. The author presents adsorption data in units of cm3 cm-3 (volumetric) rather than\nthe conventional units of cm3 g-1 and mmol g-1 (gravimetric). Could the authors clarify\nthe necessity for using volumetric adsorption and discuss its advantages in this specific\ncontext compared to gravimetric units?\nResponse: We thank the reviewer for this insightful comment. We chose to report the\nadsorption data primarily in volumetric units (cm3 cm-3) for two strategic reasons\nrelevant to the industrial scope of this work:\n(1) Industrial Relevance: For practical separation processes like Pressure Swing\nAdsorption (PSA) or Vacuum Swing Adsorption (VSA), the working capacity per unit\nvolume is the critical metric that determines the size of the adsorption column and the\noverall plant footprint. Therefore, volumetric capacity is often more meaningful for\nengineering evaluation than gravimetric capacity.\n(2) Specific Advantage of ZSTU-10: ZSTU-10 possesses a dense, robust\nframework. While its gravimetric uptake is high, its volumetric uptake is exceptional,\nhighlighting its ability to densely pack propylene molecules within a compact space.\nUsing volumetric units allows for a fairer comparison against lower-density materials,\nwhich might appear superior on a per-gram basis but would require much larger reactors\nto process the same amount of gas.\nTo ensure comprehensive data reporting, we have provided the corresponding\ngravimetric data when describing adsorption capacity for the first time. We have also\nadded a brief justification for this choice in the manuscript.\nModifications:\nManuscript: Page 7\nPage 7: ZSTU-10 achieved a saturated C H adsorption capacity of 97.7 cm3 cm-3 (60.9\n3 6\ncm3 g-1) at 1 bar and a significant C H amount of 92.5 cm3 cm-3 (57.0 cm3 g-1) even at\n3 6\n0.1 bar and 298 K, reflecting its high packing efficiency.\n4. In the synthesis and characterization section, there is an inconsistency between the\nmanuscript and the supplementary information regarding the reported cavity size. The\nmanuscript states the dimension as 8.5 × 6.3 × 6.5 Å3, whereas the supplementary\ninformation lists it as 8.5 × 6.0 × 6.2 Å3, so this mistake should be corrected for\nconsistency.\nResponse: We thank the reviewer for identifying this inconsistency. We have re-\nchecked the cavity-dimension analysis and confirm that the correct cavity size is 8.5 ×\n6.3 × 6.5 Å3 (along the three principal directions) as reported in the main manuscript.\nThe corresponding value in the Supplementary Information has been corrected\naccordingly, and we have also verified that all related text/figure captions are now\nconsistent throughout the manuscript and Supplementary Information.\nModifications:\nSupplementary Information: Page 8\nSupplementary Figure 2. Framework diagrams of ZSTU-10. (a) Coordination modes\nand Zn-O/Zn-N bond distances; (b) torsion angle between triazole and oxalate\n(54.534°); (c) cross-section of the cavity and diffusion channel along the a-axis, with\nan effective cavity size of 8.5 × 6.3 × 6.5 Å3 and pore-window apertures of 4.4 × 3.4\nÅ2; (d) diffusion channel aperture of 4.7 × 3.0 Å2, illustrating the size-matching with\npropylene and the exclusion of propane.\n5. In Fig. 3d, the C H /C H uptake ratio is not present in the figure; instead, the data\n3 6 3 8\nlikely represent the C H uptake at 0.1 bar from 243 K to 333 K.\n3 6\nResponse: We apologize for the labeling error in the original caption. The reviewer is\nentirely correct: Fig. 3d illustrates the temperature-dependent variation of C H and\n3 6\nC H uptake capacities (at 0.1 bar and 1 bar), specifically highlighting the unique trend\n3 8\nof C H adsorption across the temperature range, rather than the uptake ratio. We have\n3 6\ncorrected the figure caption in the manuscript to accurately reflect the data presented.\nModifications:\nManuscript: Page 8\nFig. 3. Gas adsorption performances of ZSTU-10, ZSTU-11, and ZSTU-12. (a)\nAdsorption isotherms of C H (square, red) and C H (circle, blue) at 100 kPa and 298\n3 6 3 8\nK. (b) The logarithmic plot of C H and C H on ZSTU-10 (red), ZSTU-11 (blue), and\n3 6 3 8\nZSTU-12 (black), differential values (∆q) of adsorption capacity for C H and C H at\n3 6 3 8\n0.1 bar. (c) Comparison of the C H volumetric adsorption among other reported sieving\n3 6\nMOFs at 0.1 bar and 298 K. (d) Temperature-dependent adsorption capacities\n(isobars) of C H and C H at 1 bar, and C H uptake at 0.1 bar, measured across the\n3 6 3 8 3 6\ntemperature range of 243 K to 333 K. (e) Time-dependent sorption profiles of C H\n3 6\n(red) and C H (blue) at 298 K and 1 bar. (f) Comparison of the diffusivity coefficient\n3 8\nand C H /C H uptake ratio among benchmark MOFs.\n3 6 3 8\n6. In Supplementary Figure 72, the components in the breakthrough curves are\nmislabeled, because the more strongly adsorbed component of C H should not be\n3 6\neluted first.\nResponse: We apologize for this oversight and thank the reviewer for the keen\nobservation. The reviewer is correct: given that ZSTU-11 is selective for C H , the\n3 6\nweaker adsorbate (C H ) must elute first, followed by the stronger adsorbate (C H ). In\n3 8 3 6\nSupplementary Fig. 72, the curve labels for C H and C H were inadvertently\n3 6 3 8\ninterchanged. We have corrected the labels in Supplementary Fig. 72 to accurately\nreflect the physical breakthrough behavior.\nModifications:\nSupplementary Information: Page 63\nSupplementary Figure 71. Experimental dynamic breakthrough curves of ZSTU-11 for\na C H /C H (50/50) mixture with a flow rate of 5 mL min-1 at 298 K. The curves reveal\n3 6 3 8\na significant co-adsorption period of approximately 15 min g-1, indicating lower\nseparation efficiency compared to ZSTU-10.\n7. The manuscript contains several grammatical and typographical errors that require\nattention. For example:\nPage 7, the term “Q ” should be defined upon its first introduction, which occurs in the\nst\npreceding sentence.\nPage 9, the multiple C-H···O interactions in ZSTU-11 are given as 2.793-3.536 Å but\nshould be corrected to 2.792-3.536 Å.\nIn Fig. 5d, the chemical formulas “C H ” and “C H ” should be formatted with\n3 6 3 8\nsubscripts as “C\n6\n” and “C\n8\n”.\nResponse: We sincerely thank the reviewer for their careful reading and constructive\nsuggestions. All highlighted errors, including the definition of “Qst”, the C-H···O\ndistance, and the labeling of breakthrough curves and chemical formulas, have been\ncorrected. We have also performed a thorough proofread of the entire manuscript and\nSupplementary Information to ensure consistency and clarity.\nModifications:\nManuscript: Page 2-3, 8-10, and 14\nPage 2: However, the strong host-guest interactions in such materials often necessitate\nsubstantial energy for regeneration. In contrast, kinetic separations rely on the\ndifferences in diffusion rates and typically feature tuned pore apertures and smooth\nsurfaces to minimize transport resistance28-31. Consequently, this approach often suffers\nfrom weak host-guest confinement, failing to discriminate between closely related\nalkanes/alkenes and resulting in low selectivity.\nPage 3: The resulting framework integrates localized molecular sieving gate to selective\nguest admission, interconnected auxiliary large channels that function as bridge-\nmediated guest diffusion pathways, and central cavity acting as high-capacity storage\nreservoirs. This gate-channel-cavity architecture cooperatively enhances diffusion\nkinetics, guest storage capacity, and host-guest binding affinities (Fig. 1).\nPage 8: Based on the adsorption isotherms at 313, 323 and 333 K, the isosteric heat of\nadsorption (Q ) of C H on ZSTU-10 was calculated to be 45.5 kJ mol-1 at zero\nst 3 6\ncoverage using the virial method. For comparison, The Q of C H on ZSTU-11 is 37.3\nst 3 6\nkJ mol-1 according to C H adsorption isotherms at 303, 313 and 323 K (Supplementary\n3 6\nFigs. 26-29).\nPage 9: It is well established that the overall adsorption performance is governed not\nonly by thermodynamic equilibrium factors, such as host-guest affinity and adsorption\nenthalpy, but also by the diffusion kinetics of guest molecules within the framework.\nPage 10: As depicted in Supplementary Fig. 62, C H molecules located in the middle\n3 6\nof the pore cavity in ZSTU-11, forming multiple C-H···O interactions (2.792-3.536 Å)\nand intermolecular d( ) C-H···N (2.999-3.246 Å) interactions with the\nC3H6···TRZ\nframework.\nPage 14: (c) Dynamic uptake of cyclic tests on ZSTU-10 for C H /C H mixtures.\n3 6 3 8\n8. The raw materials used by the author are very cheap. Has large-scale synthesis and\neconomic evaluation been conducted? This is very meaningful for practical applications.\nResponse: We thank the reviewer for this valuable question regarding the industrial\nviability of our material. We recognize that economic feasibility is crucial for practical\napplication. To address this, we conducted a preliminary scalability and cost assessment:\n(1) Recipe Optimization: We successfully optimized the synthesis protocol. We\nfound that high-purity ZSTU-10 can be synthesized not only at the initial screening\nratio (5:5:25) but also at a much more economical ratio of 1:1:5 (Zn:Oxalate:Triazole),\nwithout compromising crystallinity or adsorption performance (as verified by PXRD\nand uptake data in Supplementary Fig. 73). This significantly reduces the consumption\nof the organic ligand.\n(2) Cost Estimation: Based on this optimized 1:1:5 recipe and current laboratory-\ngrade reagent prices, we estimated the raw material cost of ZSTU-10 to be\napproximately $50.1/kg. While higher than mature zeolites, this is highly competitive\nfor MOF materials. Furthermore, we anticipate that transitioning to industrial bulk\nchemicals would reduce this cost by an order of magnitude.\nWe have added these data and the cost analysis to the manuscript and\nSupplementary Information to provide a basis for future techno-economic analysis.\nModifications:\nManuscript: Page 15\nTo assess the potential for scale-up, we optimized the synthesis conditions. We\nconfirmed that ZSTU-10 can be synthesized with high purity and crystallinity using a\nreduced molar ratio of 1:1:5, significantly lowering ligand consumption. Based on this\noptimized ratio and laboratory reagent prices, the estimated raw material cost is\napproximately $50.1 kg-1 (Supplementary Fig. 73), which serves as a promising\nbaseline for future industrial economic evaluation.\nSupplementary Information: Page 64\nSupplementary Figure 73. Scalability and cost assessment. (a) The PXRD patterns of\nZSTU-10 synthesized at different molar ratios of raw materials (5:5:25 vs. 1:1:5). (b)\nThe corresponding C H and C H uptake isotherms at 298 K and 1 bar, confirming\n3 6 3 8\nidentical performance.\nReviewer: #3\nReply to Reviewers’ Comments to Author: Referee 3\nThe authors have synthesized a MOF series, featuring central pore cages with sieving\ngates apertures connected to fast diffusion channels, using alcohol structure directing\nagents. The obtained ZSTU-10 MOF achieved a good separation of propylene from\npropane via a thermodynamic-kinetics equilibrium optimization in molecular sieving.\nThe study is meaningful, addressing the key bottleneck of thermodynamic-kinetic\ntrade-off. And the resultant propylene uptake and diffusion coefficient have exceeded\nthose of the MOFs with similar cavity-channel microstructures. The manuscript is well\nwritten, the experimental evidences are self-consistent. But still, some key questions\nneed to be answered before it is publication. The detailed comments are listed as below.\nResponse: We thank the reviewer for the constructive and thoughtful comments. We\nagree that several aspects would benefit from clearer discussion and additional\nsupporting evidence, particularly regarding the structure-directing role of the alcohols,\nthe robustness of the pore apertures upon activation, and the phase distinction among\nZSTU-10/11/12. We have revised the manuscript and Supplementary Information\naccordingly and provide a point-by-point response below.\n1. The authors addressed the structure-directing agents of the three alcohols to\ntemplate the featured pore structures of ZSTU-10, 11 and 12, they only provided the\nfinal results of the bond angles and lengths. There was a lack of a discussion of\ntheir roles on the subtle differences of the isoreticular micropores shown in Figure 1a.\nBesides, have all the solvent molecules been removed from the cavities to conduct the\nsubsequent characterizations? Will the pore apertures maintain after thoroughly\nremoving all the water and alcohol solvent molecules at elevated temperatures? It is\nsurprising that ZSTU-12 displayed a negligible N uptake compared to ZSTU-10 and\n2\n11. Overall, the authors need to carefully validate whether the three isoreticular\nstructures are de facto one accompanied with two intermediate state structures.\nResponse: We thank the reviewer for these insightful questions, which allowed us to\nclarify (1) how the alcohol structure-directing agents (SDAs) regulate subtle pore\nmetrics among the isoreticular phases, (2) whether the pore apertures are preserved after\ncomplete guest removal, and (3) whether ZSTU-10/11/12 represent distinct isolable\nphases rather than intermediate states.\n(1) Role of alcohol SDAs in tuning gate/channel/cavity metrics. In the manuscript,\nwe now explicitly discuss that the three alcohol SDAs modulate local coordination\ngeometry (e.g., N-Zn-O angles and triazole orientations), which in turn changes the\neffective gate apertures and channel cross-sections while maintaining the same\nunderlying framework connectivity. These pore-metric differences are summarized in\nFig. 1a and quantified in the Supplementary Information (Supplementary Figs. 2-4).\nThe resulting gate dimensions—ZSTU-10: 4.4 × 3.4 Å, ZSTU-11: 4.9 × 3.1 Å, and\nZSTU-12: 4.6 × 2.9 Å—provide the primary structural basis for the observed trends in\ndiffusion and separation performance.\n(2) Guest removal and aperture stability upon activation. All adsorption\nmeasurements were performed on fully activated samples (150 °C under high vacuum\nfor 12 h). We added/expanded post-activation structural validation. As-synthesized\nsamples obtained from single-crystal X-ray diffraction (SCXRD) and activated samples\nobtained from neutron powder diffraction (NPD) show that the patterns of are\nessentially identical with no detectable peak shifts, indicating preservation of the\nframework upon activation (Supplementary Figs. 15-16). The native and activated\nconformations of ZSTU-10/ZSTU-10a, ZSTU-11/ZSTU-11a, and ZSTU-12/ZSTU-\n12a all exhibit high matches and overlap. (Supplementary Figs. 7-8). In addition,\nvariable-temperature PXRD and temperature-dependent SCXRD analyses for ZSTU-\n10 support an invariant framework and stable pore apertures over the examined\ntemperature range (Supplementary Fig. 17, Supplementary Figs. 55-57, and\nSupplementary Table S1). These results collectively indicate that solvent molecules are\nremoved and that the pore apertures are retained under the activation conditions used.\n(3) Negligible N uptake of ZSTU-12 and validation of distinct phases. We agree\n2\nthat the negligible N uptake of ZSTU-12 at 77 K is notable. We attribute this behavior\n2\nto kinetic restriction of N diffusion through the narrower gate in ZSTU-12, while CO\n2 2\nadsorption confirms the presence of accessible microporosity. To further verify that\nZSTU-10/11/12 are distinct, isolable phases rather than intermediate states, we\nperformed cross-solvent soaking controls. The PXRD patterns remain unchanged after\nimmersing each material in the alcohols used to synthesize the others (Supplementary\nFig. 18), indicating that the phases are stable and do not undergo solvent-mediated\ninterconversion under these conditions.\nWe sincerely appreciate the reviewers for raising these insightful questions, which\nhave allowed us to elaborate on the structural subtleties and integrity of these materials.\nModifications:\nManuscript: Page 5-6\nPage 5: The structural robustness and phase identify of the ZSTU series were rigorously\nvalidated through complementary diffraction techniques and solvent-stability assays.\nTo assess framework integrity upon activation, high-resolution neutron powder\ndiffraction (NPD) was employed to characterize ZSTU-10/11/12. The NPD profiles of\nthe as-synthesized and activated samples (ZSTU-10a/11a/12a) exhibit high structural\nuniformity with negligible deviation. (Supplementary Figs. 6-8 and Supplementary Figs.\n11-12 and Supplementary Figs. 15-16). This structural invariance confirm that precise\ncoordination environment and pore apertures are preserved without framework\nrelaxation or collapse following the thorough evacuation of solvent molecules.\nFurthermore, systematic cross-solvent soaking experiments were conducted. Each\nmaterial was immersed in the specific alcohols used for the synthesis of its isoreticular\ncounterparts to evaluate potential phase transitions. The resulting PXRD patterns\nremained entirely unchanged (Supplementary Fig. 18), demonstrating that these\nframeworks do not undergo solvent-mediated interconversion. These results\ncollectively confirm that the three isoreticular structures are independent stable states,\nwhose specific pore metrics are inherent to the alcohol-templated assembly rather than\nreflecting meta-stable intermediates.\nPage 6: Both ZSTU-10 and ZSTU-11 exhibit type-Ⅰ adsorption behaviors for CO and\n2 2\nN uptake at 77 K, which is attributed to the kinetic restriction of N diffusion through\n2 2\nthe narrower gate aperture in ZSTU-12.\nSupplementary Information: Page 21\nSupplementary Figure 16. Comparison of experimental PXRD patterns of as-\nsynthesized and activated samples. The negligible peak shifts and consistent intensity\nprofiles confirm that the frameworks retain their structural integrity and pore geometry\nupon solvent removal.\n2. The C H uptake for ZSTU-10 at 0.1 bar has approached to the saturated adsorption\n3 6\ncapacity (97.7 cm3 cm-3) at 1 bar. The value has far surpassed other MOF sorption\nperformances. Please present a discussion on this phenomenon.\nResponse: We thank the reviewer for highlighting this notable feature of ZSTU-10. In\nthe revised manuscript, we added a dedicated discussion to rationalize the unusually\nsteep C H isotherm at low pressure, where the uptake at 0.1 bar achieves 92.5 cm3 cm-\n3 6\n3 and then reached a plateau at higher pressures (C H uptake of 97.7 cm3 cm-3 at 1 bar).\n3 6\nTo verify the proximity to the adsorption limit, we calculated the saturated C H\n3 6\nadsorption capacity of ZSTU-10 to be 109 cm3 cm-3 (based on the experimental pore\nvolume and liquid C H density). This confirms that the adsorption sites within ZSTU-\n3 6\n10 are nearly occupied even at very low partial pressures. Such adsorption behavior has\nalso been observed in other high-performance gas capture materials, such as CPL-1\n(Angew. Chem. Int. Ed. 2025, e24692). We have incorporated the relevant literature\nreferences into the manuscript. In this manuscript, we attribute this behavior to the\ncombination of: (1) strong and well-defined binding sites in the central cavity, which\nlead to a large initial isotherm slope (high henry affinity) and rapid site filling at low\npartial pressures; and (2) efficient cavity packing of admitted C H molecules once the\n3 6\nsieving gate is traversed, enabling a high volumetric capacity with only modest\nincreases in pressure. Furthermore, we have now explicitly connected these structural\nobservations with the adsorption thermodynamics and benchmarked the low-pressure\n(0.1 bar) uptake against representative sieving materials to place the performance in\ncontext.\nModifications:\nManuscript: Page 7 and 18\nPage 7: ZSTU-10 achieved a significant C H volumetric uptake of 92.5 cm3 cm-3 (57.0\n3 6\ncm3 g-1) at 0.1 bar and 298 K and reached a plateau at higher pressures. This\nexceptionally high low-pressure uptake is attributed to the synergistic effect of strong\nbinding sites within the central cavity and rapid transport through diffusion channels,\nwhich was a common adsorption phenomenon observed in advanced adsorbents\ndesigned for high-affinity gas capture44. At 298 K and 1 bar, The C H adsorption\n3 6\ncapacity reaches 97.7 cm3 cm-3 (60.9 cm3 g-1), reflecting its superior packing efficiency.\nThe excellent C H uptake of ZSTU-10 surpasses many benchmark sieving materials,\n3 6\nsuch as ZU-609 (73.1/10.8 cm3 cm-3)45, Y-abtc (63/35 cm3 cm-3)37, Co-gallate\n(66.6/17.9 cm3 cm-3)38, JNU-3a (87.5/18.7 cm3 cm-3)35, KAUST-7 (61.9/10.1 cm3 cm-\n3)45-48 at 1 bar and 0.1 bar (Fig. 3c and Supplementary Table 11).\nPage 18: 44. Wang, J. H. et al. Optimal host-guest fit in metal-organic frameworks to\nachieve record C H packing density for trace acetylene capture. Angew. Chem. Int. Ed.\n2 2\ne24692, (2025).\n3. The 50/50 propylene/propane co-adsorption analysis should be supplemented.\nResponse: We thank the reviewer for this constructive suggestion. We recognize that\nunderstanding the competitive adsorption behavior of C H /C H mixtures is crucial for\n3 6 3 8\nevaluating the separation performance of ZSTU-10. While direct C H /C H co-\n3 6 3 8\nadsorption measurement was not feasible due to current experimental instrumentation\nconstraints, we have performed a detailed quantitative analysis of the co-adsorption\nbehavior derived from the dynamic breakthrough curves. In a typical breakthrough\nexperiment, if the calculated dynamic capacity significantly exceeds the static\nequilibrium capacity, it indicates the presence of co-adsorption. When calculating the\nC H dynamic adsorption capacity directly of ZSTU-10 (without accounting for the co-\n3 6\nadsorbed C H ), the apparent C H uptake is approximately 3.72 mmol g-1. This value\n3 8 3 6\nis higher than the static adsorption capacity, suggesting the presence of co-adsorbed\nspecies in the column. By analyzing the initial breakthrough of C H , we identified a\n3 8\nco-adsorption interval of 8.6 min g-1 (at a flow rate of 5 mL min-1). This interval\nrepresents the C H that is temporarily retained or co-adsorbed alongside C H during\n3 8 3 6\nthe separation process. After subtracting the contribution of this co-adsorbed C H from\n3 8\nthe total dynamic uptake, the corrected C H dynamic capacity is 2.76 mmol g-1. This\n3 6\ncorrected value is in excellent agreement with the results obtained from our static\nadsorption isotherms. Additionally, the C H /C H co-adsorption is short a flow rate of\n3 6 3 8\n3 mL min-1, with an interval of 4.2 min g-1, whereas the corresponding C H retention\n3 6\ntime is longer (20.8 min g-1 at 3 mL min-1), enabling a clear time window for producing\nhigh-purity C H . By comparison, ZSTU-11 shows a substantially longer co-adsorption\n3 6\ninterval (15 min g-1 at 5 mL min-1), consistent with less effective dynamic separation\nunder otherwise comparable conditions. These results, together with the corrected curve\nlabeling and clarified definitions of the reported time metrics, support that ZSTU-10\ncan selectively capture C H from an equimolar mixture with minimal co-elution of\n3 6\nC H , consistent with a molecular-sieving mechanism. We have revised the manuscript\n3 8\nand Supplementary Information to include this detailed co-adsorption analysis, with\nbreakthrough curves provided in Supplementary Fig. 67).\nModifications:\nManuscript: Page 12-13\nPage 12: However, the separation efficiency distinguishes the two materials. Notably,\nat a total flow rate of 3 mL min-1, the breakthrough curves for the equimolar C H /C H\n3 6 3 8\nmixture show that C H elutes first, and the co-adsorption interval is short (4.2 min g-\n3 8\n1). After the overlap ends, a clear time window is observed in which C H is retained\n3 6\nwhile C H has already eluted, enabling a wide separation window with mass-\n3 8\nnormalized retention time of approximately 16.6 min g-1 for high-purity C H collection\n3 6\n(Fig. 5a).\nPage 13: At a higher flow rate of 5 mL min-1, ZSTU-10 maintains a limited co-\nadsorption interval (8.6 min g-1), whereas ZSTU-11 exhibits a substantially longer co-\nadsorption interval (15 min g-1) under comparable conditions (Supplementary Figs. 68\nand 72). Besides, the retention time of C H /C H for ZSTU-11 below the co-adsorption\n3 6 3 8\ninterval reveals the poor separation efficiency. The shorter overlap for ZSTU-10\nindicates reduced co-elution and thus improved dynamic separation performance for\nequimolar C H /C H mixtures.\n3 6 3 8\nSupplementary: Page 61\nSupplementary Figure 67. Equivalence verification of mass balance calculations\nusing molar flow rates and normalized concentrations. (a) Real-time molar flow rates\nof C H and C H during the breakthrough process on ZSTU-10. (b) Calculation of\n3 8 3 6\nC H adsorption capacity by integrating the molar flow rate curve: the yellow area\n3 6\nrepresents ∫\n𝑡2[𝑛\n−𝑛 (𝑡)]𝑑𝑡. (c) Calculation based on the normalized\n𝑡1 𝑖𝑛,𝑖 𝑜𝑢𝑡,𝑖\nbreakthrough curve (C/C 0 ): the yellow area represents 𝑛 𝑖𝑛,𝑖 ∫ 𝑡 𝑡 1 2[1− 𝐶 𝐶 0 (𝑡)]𝑑𝑡. Due to\nlimited testing conditions, the comparison between dynamic and static capacities serves\nas a reliable metric for understanding co-adsorption. the integration of the C H\n3 6\nbreakthrough curve initially yielded an apparent dynamic capacity of 3.72 mmol g-1\n(the calculated area 0-t ). The discrepancy between this value and the static equilibrium\n2\ncapacity is attributed to the co-adsorption of C H within the adsorbent bed during the\n3 8\ninitial stages of the breakthrough process. After deducting co-adsorbed interval of 8.6\nmin g-1 of C H /C H co-adsorption, the calculated dynamic adsorption capacity for\n3 6 3 8\nC H is as follows: the flow rate of C H : q = 2.5 mL min-1 = 0.1116 mmol min-1,\n3 6 3 6\nbetween the breakthrough point t -t : the captured amount of C H : Q =\n1 2 3 6\n∫ 𝑡 𝑡 1 2[𝐶 𝑖 0 −𝐶 𝑖 (𝑡)]𝑑𝑡 , so t 1 -t 2 area above the entire breakthrough curves gave the\ncomparatively high loading of ZSTU-10 to be 2.76 mmol g-1, corresponding to the area:\n24.732.\n4. There are many clerical errors. For example, there is no Fig. 3i in the main text, it\nshould be Fig. 3f.\nResponse: We sincerely apologize for this oversight and thank the reviewer for the\ncareful reading. We have corrected the erroneous citation from Fig. 3i to Fig. 3f in the\nmanuscript. Furthermore, taking the reviewer’s comment that “there are many clerical\nerrors” seriously, we have conducted a line-by-line proofreading of the entire text and\nSupplementary Information. We have corrected several other minor inconsistencies in\nfigure cross-references, formatting, and grammar to ensure the manuscript meets the\nhigh publication standards of Nature Communications.\nModifications:\nManuscript: Page 9, 11, and 13\nPage 9: To further quantify this distinction, the calculated diffusion coefficient of C H\n3 6\nin ZSTU-10 was 4.29 × 10-9 cm2 s-1 at 298 K and 1 bar. This value is comparable to\nZU-609 (1.36 × 10-9 cm2 s-1), and two orders of magnitude higher than other leading\nsieving materials such as Co-gallate (6.47 × 10-11 cm2 s-1), and KAUST-7 (9.49 × 10-11\ncm2 s-1) (Fig. 3f and Supplementary Fig. 9 and Figs. 53-54 and Supplementary Table\n6)50.\nPage 9: Such a high selectivity significantly outperforms most benchmark MOFs, such\nas DL-mal-MOF (62.6)40, MAF-23-O (68.8)37, Ni(AIP)(BPY) (48.3)51\n0.5\n(Supplementary Table 10)52.\nPage 11: To obtain direct structural insight into the adsorption behavior of ZSTU-10,\nhigh-resolution neutron powder diffraction (NPD) experiments were conducted to\naccurately establish the supramolecular binding forces between C D molecules and the\n3 6\nframework (Supplementary Fig. 11b).\nPage 13: As depicted in Fig. 4, site Ⅱ serves as the predominant sorption site and owns\na higher occupancy, which was anchored by the surrounding oxalate ligands to form\nmultiple C-D···O interactions (2.386-3.402 Å).\n5. Fig. 5d, why is there a peak signal for C H desorption? And how does the ZSTU\n3 6\nperform for a consecutive breakthrough cycles, like four or five times. Please present\nthe breakthrough curves.\nResponse: We thank the reviewer for these important questions regarding regeneration\nbehavior and cycling stability. The C H desorption peak observed in Fig. 5d arises\n3 6\nfrom our two-step regeneration protocol. After adsorption, the bed is first purged with\nAr at 298 K, which removes weakly bound and gas-phase components. Subsequently,\na thermal-swing step at 448 K is applied under Ar, providing sufficient energy to release\nC H from the higher-affinity adsorption sites. This temperature-triggered release\n3 6\nproduces a concentrated desorption peak and enables efficient recovery of C H .\n3 6\nTo avoid confusion, we have explicitly annotated these two regeneration stages in the\nrevised Fig. 5d and its caption.\nTo address the request for consecutive-cycle performance, we performed five\nconsecutive breakthrough adsorption/desorption cycles using an equimolar C H /C H\n3 6 3 8\nmixture (50/50, v/v). The breakthrough curves are nearly identical across cycles,\nshowing negligible changes in retention time and dynamic uptake. These results are\nnow provided in Supplementary Fig. 68 (and summarized in Fig. 5c), demonstrating\nthe excellent regenerability and cyclic stability of ZSTU-10 under the tested conditions.\nModifications:\nManuscript: Page 13-14\nPage 13: Five consecutive breakthrough adsorption/desorption measurements for an\nequimolar C H /C H mixture were carried out at the flow rate of 5 mL min-1. The\n3 6 3 8\nresults revealed consistent retention times, no obvious loss of capacity, and a sustained\nC H dynamic capture at around 3.7 mmol g-1 (Fig. 5c and Supplementary Fig. 68),\n3 6\nconfirming the excellent regenerability and cycling stability of ZSTU-10.\nPage 14:\nFig. 5. Dynamic breakthrough experiments of ZSTU-10. For calculation and\ncomparative analysis, all breakthrough time parameters are reported as mass-\nnormalized breakthrough time (min g-1). (a) Dynamic column curves in ZSTU-10 for\nC H /C H (50/50) with a flow rate of 3 mL min-1. (b) Comparison of the dynamic C H\n3 6 3 8 3 6\nuptake of ZSTU-10 with other reported C H /C H sieving materials. (c) Dynamic\n3 6 3 8\nuptake of cyclic tests on ZSTU-10 for C H /C H mixtures. (d) Dynamic adsorption\n3 6 3 8\nbreakthrough curves at a flow rate of 5 mL min-1, followed by desorption curves under\nArgon gas with a sweeping flow rate of 10.0 mL min-1. The desorption profile shows\ntwo distinct stages: an initial purge at 298 K, followed by thermal desorption at 448\nK (resulting in the concentrated C H peak). (e) Comparison of C H productivity with\n3 6 3 6\nwell-known MOFs. (f) Comparison of C H purity among other famous sieving MOFs.\n3 6\n(g) Cycling adsorption-desorption curves on ZSTU-10 at 298 K and 1 bar.\nSupplementary Information: Page 62\nSupplementary Figure 68. The five experimental breakthroughs cyclic curves of\nC H /C H (v/v = 50/50) with a flow rate of 5 mL min-1 at 298 K and 1 bar on ZSTU-\n3 6 3 8\n10. The overlapping curves demonstrate excellent cyclic stability.\nReviewer: #2\nReply to Reviewers’ Comments to Author: Referee 2\nThe authors have effectively addressed my questions and agreed to accept the\nmanuscript.\nResponse: We sincerely thank the reviewer for the positive assessment and the\nrecommendation for acceptance. We are very grateful for the constructive comments\nprovided during the revision process, as they have significantly improved the quality\nand clarity of our manuscript.\nReviewer: #3\nReply to Reviewers’ Comments to Author: Referee 3\nThe authors addressed my concern, it can be published at the present form.\nResponse: We thank the reviewer for the positive feedback and the recommendation for\npublication. We are pleased that our revisions successfully addressed all the\nconcerns. We also appreciate the reviewer’s professional support and insightful\nsuggestions throughout the review process."}, {"round": 2, "reviewer_comments": {"reviewer_2": "The authors have effectively addressed my questions and agreed to accept the manuscript.", "reviewer_3": "The authors addressed my concern, it can be published at the present form."}, "author_response": "Reply to Reviewers’ Comments to Author: Referee 2\nThe authors have effectively addressed my questions and agreed to accept the\nmanuscript.\nResponse: We sincerely thank the reviewer for the positive assessment and the\nrecommendation for acceptance. We are very grateful for the constructive comments\nprovided during the revision process, as they have significantly improved the quality\nand clarity of our manuscript.\nReviewer: #3\nReply to Reviewers’ Comments to Author: Referee 3\nThe authors addressed my concern, it can be published at the present form.\nResponse: We thank the reviewer for the positive feedback and the recommendation for\npublication. We are pleased that our revisions successfully addressed all the\nconcerns. We also appreciate the reviewer’s professional support and insightful\nsuggestions throughout the review process."}]

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