bluuebunny/crossref_metadata_2025 huggingface dataset:
PtPdSn Electrocatalysts for Nitrous Oxide Reduction
Authors: Kato Masaru , Sarker Abinash Chandro , Zheng Jinhang , Saito Fumie , Kawamura Mitsuki , Unuma Yuki , Yagi Ichizo
Published: December 2024

Nitrous oxide (N2O) is a greenhouse gas almost 300 times more potent than CO2 and an ozone-depleting gas. N2O is increasing in the atmosphere by about one ppb per year. Electrocatalysis allows us to reduce N2O to N2 under ambient conditions at room temperature and atmospheric pressure, making electrocatalysis a promising approach for the removal of N2O. The electrochemical nitrous oxide reduction reaction (N2ORR) can be catalyzed on metals such as Pd [1,2]. Although bimetallic Au@Pd core@shell nanoparticles [3] have been reported as electrocatalysts for the N2ORR, synthetic strategies and design principles of multimetallic electrocatalysts for the N2ORR are still lacking.

Herein, we report our research progress on trimetallic PtPdSn electrocatalysts for the N2ORR in acidic media, inspired by electrocatalysts for the nitrate reduction reaction (NO3RR). The electrocatalytic NO3RR to N2 proceeds via N2ORR. It has been reported that Sn/Pd-Pt(100) electrodes produce NO, N2O and N2 in the NO3RR but Sn/Pt(100) does not [4], suggesting that the Sn/Pd-Pt interface plays an important role in the electrocatalysis for the N2ORR. This study encourages us to prepare co-deposited Pt and Pd nanoparticles on fluorine-doped tin oxide using the arc plasma deposition method [5]. Pt and Pd nanoparticles deposited on fluorine-doped tin oxide show higher electrocatalytic activity for both NO3RR and N2ORR than those deposited on glassy carbon [5]. This result also supports that the Sn/Pd-Pt interface is crucial for the efficient catalysis of the N2ORR. We are now working on PtPdSn nanoparticles supported on carbon black (PtPdSn/C) for the N2ORR in acidic media [6]. PtPdSn/C shows higher N2ORR activity than bimetallic PtPd/C or PtSn/C and exhibits almost 100% Faradaic efficiency for the the N2ORR to N2 at ≥ +0.06 V vs. RHE with no competition with the hydrogen evolution reaction. The trimetallic PtPdSn electrocatalysts will be a promising candidate for the efficient removal of N2O towards a sustainable society.

References.

[1] A. Kudo, A. Mine, J. Electroanal. Chem., 408, 267–269 (1996).

[2] B.H. Ko, B. Hasa, H. Shin, Y. Zhao, F. Jiao, J. Am. Chem. Soc., 144, 1258–1266 (2022).

[3] K. Kim, J. Byun, H. Kim, K.S. Lee, H. S. Lee, J. Kim, T. Hyeon, J.J. Kim, J.W. Han, ACS Catal., 11, 15089–15097 (2021).

[4] M. Kato, Y. Unuma, M. Okui, Y. Qu, J. Zheng, S. Taguchi, F. Kiguchi, M. Torihata, Y. Gao, N. Hoshi, I. Yagi, Electrochim. Acta, 398, 139281 (2021).

[5] A.C. Sarker, M. Kato, I. Yagi, Electrochim. Acta, 425, 140628 (2022).

[6] A.C. Sarker, M. Kato, M. Kawamura, T. Watanabe, I. Yagi, submitted.
Investigating the Effect of Copper Ion Impurities on the Structural Evolution and Electrocatalytic Activity of Catalysts for HER
Authors: Saini Sonakshi , Lee Seunghoon , Wright Salem Clay , Parvin Sahanaz , Weber Juliane , Baltrusaitis Jonas , McDowell Matthew Todd
Published: December 2024

Seawater splitting has garnered significant research interest recently as a method to produce green hydrogen at reduced costs1. One major limitation is the effect of naturally present impurities on all parts of an electrolyzer2– from the membranes to the catalysts. Transition metal cations with reduction potentials in the range of the hydrogen evolution reaction (HER) could interfere with the electrocatalytic reaction. Although this effect has been investigated in the context of underpotential deposition3, there is limited understanding of how competitive redox processes involving impurity ions can influence HER on electrocatalytic electrodes. Here, we study the effect of copper as an impurity ion in the presence of electrocatalytic (platinum) and non-electrocatalytic (gold) electrodes to understand the dynamic competition between electrodeposition and HER. We find that copper deposition competes with HER on both platinum and gold surfaces, leading to a significant decrease in current density with increasing copper concentration. The electrode surfaces are characterized with scanning electron microscopy and atomic force microscopy to understand morphological evolution of the growing copper metal, and X-ray photoelectron spectroscopy is used to quantify the nanoscale thickness of deposited copper. At relatively high dissolved Cu2+ concentrations, copper metal is observed to electrodeposit uniformly on gold electrodes, whereas platinum features nonuniform copper growth with pits and channels likely due to the influence of hydrogen evolution. In situ atomic force microscopy is also used to gain insight into the nucleation and growth behavior of copper on these different electrodes. Together, the results clearly show that redox competition of copper impurities can occur even at the relatively low concentrations of Cu2+ found in seawater (~1 μM)4, highlighting the importance of studying the effect of different impurities on the catalyst under consideration. This work is intended to eventually lead to robust electrolyzers that can be used to efficiently produce hydrogen under impure input stream conditions, potentially lowering costs.

REFERENCES:

Tong, W., et al., Nature Energy (2020) 5 (5), 367

Becker, H., et al., Sustainable Energy & Fuels (2023) 7 (7), 1565

Cadle, S. H., and Bruckenstein, S., Analytical Chemistry (1971) 43 (13), 1858

Leal, P. P., et al., Sci Rep (2018) 8 (1), 14763
Investigating the Impact of Electrochemical Active Surface Area of Cu with Surfactant-Modified Carbon on Electrochemical CO2 Reduction in Acidic Electrolyte
Authors: Noh Hwiyoon , Tackett Brian Michael
Published: December 2024

Electrochemical CO2 reduction reaction (CO2RR) offers a promising avenue for transforming CO2 into valuable products, which can enable sustainable carbon utilization when powered by renewable energy sources. Traditionally, neutral or alkaline electrolytes are used in CO2RR to prevent hydrogen evolution reaction (HER). Employing such electrolytes, however, poses challenges due to homogeneous equilibrium reactions, leading to limiting CO2 availability and high energy consumption for electrolyte regeneration. Lowering electrolyte pH can address this issue and mitigate the required energy, resulting in industrially relevant efficiencies. Recent studies demonstrated encouraging results for CO2RR in acidic environments using flow cells. However, it remains unclear how conventional electrocatalysts perform under acidic conditions compared to neutral or alkaline ones. In addition, it is uncertain whether previous knowledge can be applied to acidic electrolytes in the same manner from neutral and alkaline conditions. Thus, in this study, we aim to evaluate the influence of surfactant-modified synthesis methods on the electrochemical active surface area (ECSA) of Cu and CO2RR performance in an acidic electrolyte.

Different types of surfactants were employed to synthesize size-modulated Cu nanoparticles (NPs) on carbon black. Specifically, cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), and Triton X-100 represented cationic, anionic, and nonionic surfactants, respectively. Synthesis without surfactant treatment was further performed to elucidate surfactant-driven effects. Interestingly, variations in the size and distribution profiles of Cu NPs on carbon black were observed due to two roles of surfactant used in the synthesis: surface charge modifier and capping agent. In addition, the ECSA of Cu depended on the size and distribution of Cu NPs, highlighting the importance of both small size and uniform distribution to maximize ECSA. Finally, CO2RR activity was measured in a lab-made flow cell using 0.1 M H2SO4 with 0.4 M K2SO4. It was observed that large ECSA was beneficial to promoting CO2RR over HER with selective production of C2H4 over CH4 while the intrinsic activity of Cu itself was maintained. It was additionally reported that the selectivity of C2H4 over CH4 in the acidic electrolyte was more than 5 times higher than that in a neutral electrolyte, emphasizing the importance of the use of acid for CO2RR. Overall, this work provides critical electrocatalyst design criteria for efficient C2H4 production under acidic environments.
(Keynote) Understanding Interfaces in Electrochemical CO2 Reduction, from Model Systems to Applied Platforms
Authors: Jaramillo Thomas F.
Published: December 2024

The development of new technologies for the sustainable transformation of CO2 into value-added fuels and chemicals is a promising approach to meet global needs. This paper will cover research efforts to understand electrified interfaces for CO2 reduction. Fundamental studies of well-defined catalyst materials and electrolyte conditions uncover the role of the microenvironment in steering catalytic activity, selectivity, and durability. Studies of more applied platforms with greater complexity provide insights into the roles of mass transfer, flooding, and crystallization. Translating knowledge from model systems to applied platforms is key to enabling high-performance technologies in this space.
(Keynote) Controlling CO2 Electrolyzer Reactivity Using Alloy and Polymer-Modified Electrodes
Authors: Gewirth Andrew A. , Chen Xinyi , Wang Heryn , Kenis Paul J.A
Published: December 2024

This talk addresses the reactivity associated with CO2 reduction. Electrodeposition of metals from plating baths containing 3,5-diamino-1,2,4-triazole (DAT) as an inhibitor yields highly porous materials exhibiting enhanced activity for electrochemical reactions. Electrodeposition of Cu or CuAg and CuSn, alloy films from such plating baths yields high surface area catalysts for the active and selective electroreduction of CO2 to multi-carbon hydrocarbons and oxygenates. EXAFS shows the co-deposited alloy film to be homogenously mixed. Alloy films containing Sn exhibit the best CO2 electroreduction performance, with the Faradaic efficiency for C2H4 and C2H5OH production reaching nearly 60 and 25%, respectively, at a cathode potential of just –0.7 V vs. RHE and a total current density of ~–300 mA/cm2. Alloy films containing Sn exhibit greater efficiency for CO production relative to either Cu alone or CuAg at low overpotentials. In-situ Raman and electroanalysis studies suggest the origin of the high selectivity towards C2 products to be a combined effect of the enhanced destabilization of the Cu2O overlayer and the optimal availability of the CO intermediate due to the Ag or Sn incorporated in the alloy. Sn-containing films exhibit less Cu2O relative to either the Ag-containing or neat Cu films, likely due to the increased oxophilicity of the admixed Sn. Additionally, modification of the Cu electrode with certain polymers (Figure 1) yields substantially enhanced reactivity, due in part to control of the Cu2O layer and elevated surface pH, measured in situ. These electrodes exhibit enhance ethanol production. Polymer-composite electrodes exhibit enhanced reactivity over a wide range of proton-involved electrochemical reactions, such as methanol oxidation and oxygen reduction.
Comparative Selectivity of CO and CO2 Reduction Using Cu Electrocatalysts in Zero-Gap MEA Cells
Authors: Bello Mustapha , Dauda Monsuru Olatunji , Hendershot John C , Park Junghyun , Agbadan Ignace , Tasnim Soundarzo , Flake John C.
Published: December 2024

The electrochemical reduction of CO2 to C2 products is believed to proceed via the formation of adsorbed CO as an intermediate. Although ethylene is frequently reported as the main product when using Cu electrocatalysts, recent studies have demonstrated that directly feeding CO can result in the selective formation of acetate. In this study, we investigate the electrochemical reduction of CO2 and CO using Cu electrocatalysts prepared by a one-pot synthesis method employing hydrazine as a reducing agent and polyvinylpyrrolidone (PVP) as a capping agent in a Membrane Electrode Assembly (MEA) cell configuration. We investigated the electrochemical reduction of CO2 and CO using Cu electrocatalysts prepared by a one-pot synthesis method in a Membrane Electrode Assembly (MEA) cell configuration. While CO2 reduction primarily yields ethylene (36.99%), followed by hydrogen, CO, and ethanol, feeding CO directly under the same potential increases the total C2 product yield from 52% to 83%, with acetate becoming the dominant product at 63%. Employing a phosphate buffer to maintain an alkaline pH of 8 further enhances acetate selectivity, reaching 90% with KOH. We propose a mechanism involving a common acetyl intermediate for ethylene formation from CO2 and a ketene intermediate for CO reduction to acetate. Our results highlight the significant impact of feed, electrolyte composition, and pH on product distribution, with direct CO reduction favoring C2 products and alkaline pH promoting acetate selectivity. These findings offer insights for optimizing the electrochemical reduction of CO2 and CO.

Figure 1
Enabling Photoelectrochemical CO2 Reduction Catalyzed by a Molecular Iridium Catalyst Anchored Onto Oxide-Coated Silicon
Authors: Shin Samuel Jaeho , He Shi , Keller Landon , Tereniak Stephen , Nevia Sampaio Renato , Dones Lassalle Christian Y , Powers Rebecca , Yang Hyuenwoo , Jordan Aldo , Parsons Gregory N. , Cahoon James , Leibfarth Frank A , Miller Alexander J. M. , Dempsey Jillian Lee
Published: December 2024

(Photo)electrochemical CO2 reduction (CO2R) has been of great interest not only for its promising route to economic, transportable, storable, and sustainable fuels,but also for the fundamental study of factors that impact the identity of the reaction product(s). Among such well-behaved catalytic systems, the pentamethylcyclopentadienyl-ligated Ir(III) half-sandwich complex with 2,2’-bipyridine derivatives is a representative class with both electrochemical and photochemical CO2R catalysis reported. However, its photoelectrochemistry for CO2R has scarcely been studied.

In this work, we investigated the potential utility of half-metallocene Ir(III) complex anchored onto SiO2-coated silicon (prepared via rapid thermal annealing) and TiO2-coated silicon (prepared via atomic layer deposition) as a hybrid system and investigated their photoelectrochemical properties under illumination. Both formate and CO were produced from CO2
with high turnover numbers. Current investigations are focused on understanding how surface anchoring impacts selectivity.
CuSx Catalysts for CO2 Electrolyzer Cathode
Authors: Ha Juho , Ahn Sang Hyun
Published: December 2024

Because of the climate crisis caused by increasing atmospheric CO2 concentration, developing technologies for reducing them has become imperative. Among various tries, electrochemical CO2 reduction reaction (ECRR) is one of the promising solutions for carbon dioxide recycling as it can be used for the production of more valuable industrial chemicals(e.g. syngas, CO, formic acid...) in a clean way.

Ethylene, one of the products, has a high market price of 1.30 dollars/kg. It has various uses for polyethylene production and ethylbenzene synthesis. Ethanol is 1.00 dollars/kg and can be used as fuel. In addition, formic acid has a high value of 0.74 dollars/kg and is used in preservatives and anti-bacterial agents. Carbon monoxide can be easily converted into other hydrocarbon forms through Fischer-Tropsch synthesis

For electrolysis, gas diffusion layer(GDL) based electrolyzers have been used. This is because carbon dioxide has a solubility limit of 33 mM, so humidified carbon dioxide in the form of a gas is used to overcome this up to 41 mM. The hybrid flow cell is an electrolytic bath in which a gas diffusion layer and a cathode liquid layer are separated from the anode by a polymer membrane. It is easy to collect liquid products generated from the cathode side, but it has resistance by the liquid layer. The MEA electrolyzer is an AEMWE-based electrolytic bath in which the cathode liquid layer has been removed. Since the electrode and the membrane are in direct contact and contain a small amount of liquid, a three-phase interface is formed, resulting in an electrolytic reaction.

Focusing on the catalyst, Cu is the only mono-metal that shows decent selectivity for multi-carbon products(e.g. ethylene, ethanol, acetate, propanol...). For decades, various researches have been conducted on the development of Cu catalysts through bi-metal composition, oxidation state control and about grain boundaries, crystal facet, single-atom. However, it still has challenges about low partial current density and insufficient stability to commercialize.

Herein, copper sulfide catalysts were fabricated on gas diffusible carbon paper with microporous layer(MPL/CP). First, Cu nanoparticles were electrochemically deposited on the MPL/CP. Subsequent immersing it into Na2S solution enables ionic exchange of surface oxygens with S ions. Because the copper sulfide state has low solubility product constant, so is thermodynamically more stable. As reported, sulfur can change the distance between metal molecules, their oxidation state and their morphologies. By adjusting the exchange condition, the catalyst morphology and surface composition can be easily controlled. The fabricated electrodes were employed as cathodes for CO2RR electrolyzer and its faradaic efficiency(FE) was computed. It was revealed that the CO2RR performance was highly affected by S coverage on Cu surface. At some point the existence of Sulfur changed selectivity by enhancing the FE of ethylene and oppressing FE of methane.
Tin Oxide Catalysts for Formate-Selective Electrochemical Reduction of CO2
Authors: Park Gisang , Seo Dongho , Nam Ki Min
Published: December 2024

Electrochemical reduction of CO2 (eCO2RR) to multicarbon products in aqueous solution is an important and challenging study to overcome the global climate change issue. Many recent mechanistic studies reported electrochemical CO2 reductions in different aspects such as intermediate species, reaction paths, reaction rate-determining steps(RDSs), and the influence of electrolyte. Unfortunately, the reaction selectivity of C2+ products is still limited because the identification of RDS, as the most critical mechanism guide, still lacks comprehensive and convincing evidence. Currently, two mechanisms have been generally proposed as the potential RDS through theoretical calculation(density function theory, DFT), including *CO-*CO coupling and the protonation of *CO to *CO(H).

Here, we prepared Ag-decorated Cu(I) oxide to perform electrochemical CO2 reduction to C2+ with high reaction selectivity. The prepared Cu2O-Ag catalyst shows up to 35.4 % and 30.1 % C2H4 and ethanol selectivity, respectively in CO2-saturated 0.1 M KHCO3 electrolyte. In the eCO2RR, Ag nanoparticles (Ag NPs) are known as a selective CO2 to CO conversion catalyst showing over 90 % reaction selectivity (Faradaic efficiency, FE). Hence, the decorated Ag NPs reduce the energy barrier of CO2 to CO conversion, thereby producing C2+ products(C2H4, ethanol) by facilitating *CO-*CO coupling on the Cu catalyst surface. To clarify the reaction mechanism on the Cu surface, in-situ Raman has been evaluated and revealed CO*, CH*, and OH* reaction intermediate signals at different applied potentials. This work clarifies the RDS of C2+ production in eCO2RR, and the different roles of Ag NPs in (100) and (111) Cu crystal facets.

Figure 1
Electrified Reactive Capture: System and Catalyst Designs
Authors: Xie Ke , Sargent Edward Hartley
Published: December 2024

Direct-air capture (DAC) of CO2 often uses alkali hydroxides as sorbent and relies on an energy-intensive thermal CaCO3/Ca(OH)2 step to release CO2 and regenerate the alkali hydroxide. Reactive capture converts the captured CO2 to value-added products while regenerating the captured liquid. Here we introduce the limitation factors of performance in prior electrochemical reactive capture systems. We explore system and catalyst designs to manipulate the mass transfer, maximize CO2 availability and optimize the catalyst's electronic properties. As a result, we report a carbonate-to-syngas system using this reaction-capture approach has a projected energy efficiency of 50% at 200 mA cm–2 when H2 is added to provide 2:1 H2:CO syngas by coupling with a water electrolyzer. Durability studies show 40 h of initial operating stability.
Crystallographically Vacancy-Induced MOF Nanosheet As Rational Single-Atom Support for Accelerating CO2 Electroreduction to CO
Authors: Cho Jin Hyuk , Kim Soo Young
Published: December 2024

To attain a circular carbon economy and resolve CO2 electroreduction technology obstacles, single-atom catalysts (SACs) have emerged as a logical option for electrocatalysis because of their extraordinary catalytic activity. Among SACs, metal–organic frameworks (MOFs) have been recognized as promising support materials because of their exceptional ability to prevent metal aggregation. This study shows that atomically dispersed Ni single atoms on a precisely engineered MOF nanosheet display a high Faradaic efficiency of approximately 100% for CO formation in H-cell and three-compartment microfluidic flow-cell reactors and an excellent turnover frequency of 23,699 h−1, validating their intrinsic catalytic potential. These results suggest that crystallographic variations affect the abundant vacancy sites on the MOF nanosheets, which are linked to the evaporation of Zn-containing organic linkers during pyrolysis. Furthermore, using X-ray absorption spectroscopy and density functional theory calculations, a comprehensive investigation of the unsaturated atomic coordination environments and the underlying mechanism involving CO* preadsorbed sites as initial states was possible and provided valuable insights.

Figure 1
Water Clustering Modulates Activity and Enables Hydrogenated Product Formation during Carbon Monoxide Electroreduction in Aprotic Media
Authors: Fejzic Hannah , Kumar Ritesh , Gomes Reginaldo , He Lilin , Houser Theodore J. , Kim Jaemin , Amanchukwu Chibueze , Molten Nora
Published: December 2024

As the effects of climate change are becoming increasingly visible, carbon dioxide electroreduction reaction (CO2RR) is gaining popularity to convert waste carbon dioxide to value-added products. As carbon monoxide (CO) is a key intermediate for valuable products such as methane and ethylene, CORR is studied to bypass CO2 activation. Most of the work on CO2RR and CORR has focused on using water as a proton source as water’s hydrogen bonding supports key intermediates and acts as a proton source for hydrogenated products. Using nonaqueous solvents instead of water decreases the competitive hydrogen evolution reaction (HER) from water breakdown. Additionally mixed aqueous-nonaqueous systems allow for fundamental understanding of water’s role in electrochemical transformations when it is only available in limited quantities as a proton source. Here, we experimentally control water speciation and activity using aprotic solvent media during CORR. Remarkably, we show that aprotic solvents that support microheterogeneous water-water clusters leads to significant amounts of CORR products (methane and ethylene) with a maximum ethylene Faradaic efficiency of 22% in acetonitrile (χH2O = 0.2); the first report of CORR to C2+ products using water in an aprotic solvent. In contrast, microhomogeneous systems – where water integrates into the solvents’ intermolecular binding network at all length scales and has lower water activity – primarily support undesired HER. Insights gained expand our understanding of water activity and nonaqueous electrolyte design for other important transformations reactions beyond CO reduction such as CO2RR and HER.
Charge-Selective Electrochemical Detection through Electrolyte Adsorption on Indium Tin Oxide Electrodes
Authors: Kim Yuri , Seo Minjee
Published: December 2024

In the field of electroanalytical methods, selective sensing of target analytes is as crucial as sensitive detections, as interfering substances coexist in real samples. Therefore, various strategies have been developed to enhance the selectivity of electrochemical sensors, including molecularly imprinted polymers, enzymes, or nanostructured electrodes. Modifying the charge of electrode have been also developed, which leads to charge-based discrimination, and eventually resulting in selective electrochemical sensing of charged species. For example, the introduction of negatively charged functional groups (e.g., carboxyl groups) on electrodes has shown selective detection towards positively charged species (e.g., dopamine). However, such approaches require complex materials that are customized for specific target redox species, which limits their wide applicability. In this work, we utilized the adsorption of electrolyte anions on bare indium tin oxide (ITO) electrodes to control the surface charge of the electrode and thus enable charge-based discrimination of redox species. By using polyprotic acid anions as electrolytes and varying the solution pH to determine their protonation states, we could systematically assess the electrochemical response of adsorbed charge density towards negative, positive, and neutral redox species. Furthermore, the anion effect was applied to the selective detection of dopamine in the presence of the two representative interfering species in blood, ascorbic acid and uric acid. We expect that the electrolyte-derived surface charging of the ITO electrode could be a widely applicable strategy for the selective detection of charged analytes.
Impact of Solvent-Induced Morphological Changes on Hole Transfer Dynamic during Charge Separation Process
Authors: Lee Dongchan , Cho Shinuk
Published: December 2024

Despite a clear elucidation that the change in PM6:Y6 morphology with different solvents affects photovoltaic performance, the charge dynamics during the charge separation process resulting from these morphological changes have not been extensively studied. However, studies on mobility and photocurrent have shown that holes play a crucial role in charge generation and separation.

In the conventional fullerene-based organic photovoltaics (OPVs), in which the excited electrons from the donor are transferred to the acceptor, an electron charge transfer state (eECT) that electrons pass through has a great influence on the device performance. In the bulk-heterojunction (BHJ) system based on low band-gap non-fullerene acceptor (NFA), however, a hole charge transfer state (hECT) from the acceptor to the donor has a greater influence on the device performance.

In PM6:Y6 devices fabricated using chlorobenzene (PM6:Y6-CB), the reduced exciton dissociation probability is attributed to changes in hole transfer states due to morphological variations. In PM6:Y6 devices fabricated using chloroform (PM6:Y6-CF), the hole transfer state (hECT) and Y6 highest occupied molecular orbital (HOMO) were almost degenerate. Consequently, the formation of lower effective hECT, which can interfere with hole transfer, was minimized. Conversely, in PM6:Y6-CB, the overlapping region of hECT and Y6 HOMO shifts to a lower energy side, creating a significantly lower effective hECT, which is energetically unfavorable for hole transfer. These findings from electroluminescence deconvolution analysis were validated using time-resolved photoinduced absorption spectroscopy. Consequently, the decrease in fill factor and current density in PM6:Y6-CB can be attributed to compromised hole transfer from Y6 HOMO to PM6 HOMO. This analysis underscores the importance of morphological changes in nonfullerene acceptor solar cells on hole transfer levels, ultimately affecting the charge separation efficiency.

Figure 1
Engineered Catalyst Patterns on Hematite Photoanodes for Improved Photoelectrochemical Water Oxidation Efficiency
Authors: Lee Suyeon , Lim Sung Yul
Published: December 2024

The heavy dependence on fossil fuels is a major contributor to global warming, creating an urgent need for a swift transition to renewable energy sources like solar irradiation. Photoelectrochemical (PEC) cells present a promising method for converting solar energy into chemical fuels. However, the current efficiency of PECs is inadequate for large-scale commercialization. One key obstacle to improving PEC efficiency lies in the complex and inefficient processes, from photon absorption by semiconductors to the selective transfer of photogenerated charges to redox species in the electrolyte. This study proposes a novel approach to boost PEC performance by utilizing three-dimensionally patterned catalysts on solution-processed metal oxide semiconductors, focusing on optimizing the crucial electrolyte | catalyst | semiconductor interface. By applying patterned cobalt-based catalysts onto hematite (α-Fe2O3) nanorods through a photomask-free, light-guided electrodeposition technique, we achieve direct control over the catalyst's location and distribution on the photoelectrode without relying on photolithography. The resulting electrolyte | patterned catalyst | α−Fe2O3 interface not only ensures sufficient light absorption in the front-illumination setup but also enhances the transport and transfer of photogenerated holes across the interface, reducing carrier recombination and minimizing parasitic light absorption and scattering by the catalytic layers. We confirm that electrodeposition on hematite does not affect the semiconductor's energy profile, including key parameters such as flat-band potential, carrier density, and band structure. The improved performance in PEC water oxidation is primarily due to the increased light absorption achieved by our patterned catalyst | α−Fe2O3 photoelectrode, as demonstrated by UV-Vis spectroscopy absorbance data.
Passive Haptic Gloves with Embedded Sensors for Immersive Virtual Reality Training
Authors: Kamat Vivek , Alvarado Isbela , Bhansali Shekhar
Published: December 2024

Considering the increasing demand for the integration of haptic feedback into virtual reality (VR) devices, we studied and developed a multi-sensor and actuator array for real-time perception in virtual reality for training first responders. The sensors respond to users’ interactions in the VR world and actuate the response in the real world to create realistic sensory perception [1–2]. Though several haptic device applications have been created [3], very few of them have investigated the integration of an all-in-one sensory feedback mechanism. This paper presents a novel haptic feedback glove that helps with virtual reality training applications by utilizing all-in-one sensory feedback of heat, and cold. We investigated heat and cold sensing by incorporating peltiers and microheaters into the multi-functional haptic glove to generate the radiation of heat and cold. This version of the glove functions on three components: a microcontroller (ESP32), thermocouple modules that work as sensor elements (-55°C to 125°C), polyimide heater plate films, and micro Peltiers (12V max at 12W max) that work as actuators. These three modules are responsible for creating thermal haptic feedback, which communicates with the virtual environment world and the local environment to create the sensation of heat and cold, as shown in Fig. 1(a). When the user touches a hot or cold object in virtual reality, the hand tracking recognizes the element triggering the actuators, which are controlled by the sensor to regulate the temperature. We utilized Unreal Engine 5 (UE5) and two frameworks to enable serial and Bluetooth data communication between UE5 and the microcontroller for the high-risk training simulation. Based on Fig. 2 (a), after carefully testing, the distance between the data transfer start and maximum temperature output was about a full arm’s length in real life. This could be translated to 2 to 3 feet in distance. In the case of Fig. 2(b), we see multiple negative voltages applied to the Peltier device, producing the following equation:(1).In eq.1, A is the ambient temperature, T is the temperature of the object, D is the max distance of when the user starts feeling the object’s temperature, and t is the temperature of the finger because each Peltier is individually controlled. The heating ramping rate was 4 seconds from room temperature to 60°C and for cooling, the ramping time was 8 seconds from room temperature to 10°C. The currently developed glove demonstrates for the first time the integration of heat and cold sensing for VR applications. The developed prototype glove will be used for implementing training in VR for safety officers, military, and first responders.

Figure 1
High-Sensitivity Glucose Sensor Utilizing Various Nanostructures and Electric Double-Layer-Gated Field-Effect Transistor Configuration
Authors: Hung Sheng-Chun , Lee YI Hua
Published: December 2024

This study presents an innovative approach to fabricate a high-sensitivity and low detection limit glucose sensor by employing various nanostructured materials in conjunction with an electric double-layer-gated field-effect transistor (FET) configuration. The nanostructured materials utilized include nickel nanowires, cuprous oxide, copper oxide/nanocarbon tube composites, and nano gold/zinc oxide composite materials. The enhanced detection capability is attributed to the utilization of a novel biosensor structure with unique features: an electrical double-layer gating configuration combined with nanostructures. By applying an external voltage to ions in the aqueous solution, an electric double-layer structure is formed, leading to the generation of a capacitance effect. This unique configuration creates a strong field environment, resulting in ultra-high sensitivity, which consequently leads to an exceptionally low detection limit. The innovative approach adopted in this research enhances the sensitivity of nanostructured materials for glucose sensing, enabling the detection limit to effortlessly reach 0.1nM or even lower concentrations. Compared to existing literature, our method significantly improves the detection limit by 10 to 100 times, indicating significant progress in enhancing the performance of glucose sensors.
Early Diagnosis of Autoimmune Diseases through Electrochemical Bio-Sensing Using Modified Plastic Chip Electrode
Authors: Patel Kinjal Bajiravbhai , Luhar Sunil , Srivastava Divesh Narayan , White Paul , Cole Ivan
Published: December 2024

Detecting chronic autoimmune disorder (AD) early reduces the risk of morbidity, disability, and mortality as well as offers the possibility of significant therapeutic action on time. Developing low-cost, reliable and sensitive sensors for AD may fulfil the utilization of healthcare resources in the most efficient way at earlier stages. Here, we report on the development of an electrochemical biosensor for the sensing of CXCL10 (a chemokine), a protein that is seen as a biomarker for autoimmune diseases. The self-assembly strategy is used for the immobilization of biorecognition elements on plastic chip electrodes (PCE). A homemade PCE offers a versatile and cost-effective scaffold for sensing applications. Gold nanoparticles were electrochemically deposited on the electrode via the reduction of gold ions on the PCE galvanostatically. The CXCL10 antibody and recognition elements were immobilized on gold-deposited PCE. The attachment of recognition molecules has been confirmed by energy-dispersive scanning electron microscopy, atomic force microscopy, infrared spectroscopy and electrochemical techniques. Electrochemical impedance spectroscopy has been used for the detection of CXCL10 within a concentration range spanning from pico- to micromolar range. The optimized sensor reveals the selective discrimination of CXCL10 from other chemokines at very low concentration. A relative standard deviation (RSD) of 4.78% was determined from 6 measurements, affirming the good reproducibility of the sensor. The sensor exhibited remarkable linearity both in the buffer (R2=0.988) and plasma (R2=0.987) solutions, with LOD up 0.72 pg/mL.

Figure 1
Biosensing Platform for Neuron Optical and Electrical Signals Monitoring
Authors: Wu Siqi , Zhou Lang , Kang Xuejia , Wu Shuai , Chen Pengyu
Published: December 2024

Implantable neural devices are increasingly researched for their ability to identify complex neuronal circuits and manage neurodegenerative diseases. These devices provide high temporal resolution for real-time signal monitoring but have limited spatial resolution due to the dense packing required for their electrodes, which is inferior to optical methods. On the other hand, optical methods are often less invasive than purely electrical approaches because they can be applied externally or with minimal invasion to living beings. Here we report a sensing system capable of detecting both electronic and optical signals in neuron cells. This dual-sensing capability offers several advantages for both research and therapeutic purposes. It allows for precise imaging of neuron networks, enhances data collection through combined electrical and optical monitoring, and facilitates the development of advanced therapeutic techniques with reduced invasiveness. This integration enhances the understanding of brain activity and potentially provides insights to treatments for neurological disorders.
Outstanding Humidity Sensing Material at Room Temperature: Single Crystal K0.8Ti1.73Li0.27O4 (KTLO) with New Structure
Authors: Hwang Jeong Yun , Kim Yong Hwan , Ji Sang Hyun , Choi Myung Sik , Jin Changhyun , Lee Kyu Hyoung
Published: December 2024

Until now, K0.8Ti1.73Li0.27O4 (KTLO) material has been used in various applications such as catalysts and batteries. Typically, KTLO was employed in the form of poly-crystal, but not show good characteristics in the humidity sensor field. In this study, we successfully synthesized a single crystal KTLO material with a new structure, controlling the arrangement of potassium atoms. And it can be used as a portable sensor. It was developed that can stably detect moisture in the full range (RH 0.2-99%) in real-time at room temperature, anytime, anywhere. Furthermore, it exhibits incredibly fast reaction and recovery speeds. In particular, a new KTLO polarization phenomenon, lattice distortion, molecular sliding system, and lattice elasticity mechanism that enable fast response and recovery were presented. This is generally believed to be a surface reaction as the mechanism of gas sensors, but KTLO also has a structural effect and appears to be because moisture causes a reaction while retaining moisture molecules rather than giving electrons through direct bonding. This measures the instantaneous increase or decrease in humidity present anywhere on Earth in real-time. Therefore, a wide range of applications are possible, from survival such as disaster relief in water-scarce countries, to cutting-edge semiconductor fields that are sensitive to humidity.
Enhanced Reliability of NO2 Chemiresistive Room Temperature Sensor Based on SnSeX and Its Module Integration
Authors: Hwa Yeongsik , Je Yeonjin , Jung Hyunsung , Chee Sang-Soo
Published: December 2024

Two-dimensional SnSeX (X = 1, 2) are becoming increasingly recognized as a semiconductor-type gas sensor at room temperature, owing to their high mobility, high speed, and low-power consumption. They particularly present excellent NO2 detection properties due to the strong interaction with NO2 molecules, whereas the reliability of their resultant sensors has been still unclear. To enhance the reliabilities of SnSeX sensors, intensive investigation of well-constructed single-phase SnSe and SnSe2 is significantly essential, unlike relying on additional modification to boost gas responses. Here, we explore the quantitative phase transition using the phase regulator, 1-dodecanethiol (1-DDT) to prepare well-constructed SnSeX, in the hydrothermal synthesis. As the amount of 1-DDT was controlled from 0 μL to 1200 μL, the orthorhombic SnSe phase gradually transformed into SnSe2, exhibiting a superior gas response of 1450% when exposed to 5 ppm of NO2. This well-constructed SnSe2 also exhibited highly reliable gas detection properties, despite the repeated extreme changes in NO2 gas concentration (500 ppb to 5 ppm) under humidity condition. This is because highly crystalline SnSe2 was synthesized by optimal amount of 1-DDT. Using optimal SnSe2, we finally integrated a NO2 gas sensor module capable of monitoring NO2 gas of unknown concentration.
(Invited) Developing Sensor Strategies for Drug Monitoring and Detection
Authors: Dennany Lynn
Published: December 2024

Within a clinical and forensic environment, the need for rapid, portable, sensitive and selective detection and diagnosis is one of the fore front challenges within current sensor development. Electrochemiluminescence (ECL) offers a unique option to fulfil these demands.

ECL uses redox reactions to generate light at an electrode surface is gaining increasing attention for biosensor development due to its high sensitivity and excellent signal to noise ratio. Through modulation of the ECL luminophore and the energetics of the reaction, different luminophores can be used for the detection of multiple analytes for rapid and portable detection. The use of ECL active materials such as nanomaterials to offer the ability to tune the ECL emission and the potential at which ECL is achieved dependant on the analyte of interest.

It is anticipated that the incorporation of these highly luminescent and ECL active compounds into sensor development would lead to significant decreases in detection limits. In this contribution, we report on the impact of incorporating these novel complexes into sensor devices on the ECL efficiency as well as the ability of these to improve the detection sensitivity and decrease the limit of detection using the reagent free detection of model analytes. The real world impact of these compounds will be elucidated through the comparison with more standard ECL materials such as ruthenium based compounds. The potential for multiple applications will also be examined within this contribution.

This work will examine the potential of an ECL sensor to sensitively and selectively medically relevant biomarkers in bodily samples. This will form the basis of a proof of concept for the provision of novel, flexible and innovative solution to the detection of target drugs and active metabolites which might be present in biological samples, such as breath, urine and/or blood. The key objective will be to determine the feasibility of this electrochemical technique for portable testing for illicit drugs.

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Preparation of Spherical Hollow Particles from Polyaniline Derivatives and Their Use in Ammonia Gas Sensing Materials
Authors: Matsuguchi Masanobu , Kori Hieoki , Kojima Hibiki
Published: December 2024

The ammonia gas sensing properties of polyaniline (PANI) derivatives with different substituents were investigated. By introducing a bulky substituent into PANI, the π-π stacking was reduced, making it easier for ammonia molecules to approach the reaction sites. In addition, hollow spherical particles of polyaniline derivatives were prepared by optimizing the polymerization conditions. The use of hollow spherical particles as sensing materials resulted in a shorter response time and improved reversibility. There are two possible reasons for this improvement. First, by making the spherical particles micrometer-sized, many voids were created in the sensing film. In addition, by making the spherical particles hollow, gas molecules were able to approach the reaction sites from both the outside and the inside of the particles.

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Hydrodynamic Jet Cavitation to Process Natural Graphite into High C-Rate Capable Anodes for Use in Pouch Cells
Authors: Robinson Benjamin , Low John
Published: December 2024

A novel method for processing natural graphite for use in high performance Li-ion batteries is presented. The processing method utilises hydrodynamic jet cavitation (HJC) to produce a highly conductive graphite powder from a natural graphite precursor with the only consumables being electricity and water (process shown in Figure 1a). The HJC process produced a thin (carbon black)-like coating on the surface of the graphite particles, giving the material a higher conductivity compared to two other commercial graphite samples. In rate capability tests, LFP // graphite full cells produced a specific capacity 500% than the commercial graphite anodes (Figure 1c).

This patented process is carbon neutral and aims to help the global electric vehicle (EV) market to produce high performing EVs whilst simultaneously lowering the high carbon footprint from producing the battery packs that power them.

An in-depth characterisation study is performed on the powders, electrode slurry formulations and cells to determine how the surface characteristics of the graphite particles affect their electrochemical performance. The graphite powders were separated by particle size and tested in both coin and single layer pouch cells. Through SEM analysis, HJC graphite powders show a higher proportion of edge planes compared to basal planes, providing more sites for Li (de-)intercalation during charging and discharging (shown in Figure 1b). This explains their higher capacity at higher C-rates (5C + 10C) compared to the commercial standards. However, it is also found that the higher proportion of edge planes results in a substantially thicker solid electrolyte interphase (SEI) during cycling, consuming more of the Li inventory; resulting in a poorer initial coulombic efficiency and cycle life. The addition of electrolyte additives such as Lithium difluorooxalatoborate (LiDFOB), vinyl carbonate (VC) and VC derivatives are used to improve the coulombic efficiency of the coin and pouch cells.

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Ethyl Cellulose As a Sustainable Binder for Activated Carbon Electrodes in Supercapacitors
Authors: Fone Thomas M. , Jones Daniel Raymond , Phillips Christopher O. , Chasri Aphidet , Deganello Davide
Published: December 2024

Supercapacitors offer a blend of battery-like energy density and capacitor-like power density, a potentially very useful component in tandem with regular batteries for both electric vehicles and grid scale energy storage devices (1). This work explores the testing of a high-performance, environmentally sustainable alternative binder for supercapacitors. the choice of binder is crucial, especially for aqueous electrolyte systems where the binder cannot be water soluble.

Commonly researched binders like PTFE or PVDF (2) pose environmental and toxicity concerns, necessitating the search for more eco-friendly options. This study focuses on Ethyl Cellulose, a plant-derived polymer binder, for synthesizing activated carbon electrodes for Electrical Double Layer Capacitors (EDLCs).

Through systematic experimentation, the impact of binder concentration on electrode electrochemical performance has been explored . Notably, by varying the concentration of Ethyl cellulose, The measured capacitance per gram of active material can be more than doubled. This shows the potential of Ethyl cellulose as a greener alternative binder for supercapacitors, offering both high performance and sustainability. Furthermore, testing parameters utilized for electrochemical evaluation and materials characterization are outlined , providing insights into the comprehensive assessment of electrode performance.

Zhang, J., Gu, M. and Chen, X. (2023) ‘Supercapacitors for renewable energy applications: A Review’, Micro and Nano Engineering, 21, p. 100229. doi:10.1016/j.mne.2023.100229.

Zhu, Z. et al.(2016) ‘Effects of various binders on supercapacitor performances’, International Journal of Electrochemical Science, 11(10), pp. 8270–8279. doi:10.20964/2016.10.04.