Electrocatalytic Reaction Research Articles

Insight into the Coupling of HgS and CuO with Metal-Organic Frameworks Support in Electrocatalytic Oxygen Evolution Reaction.

This study investigates the coupling of mercury sulfide (HgS) and copper oxide (CuO) nanoparticles with metal-organic frameworks (MOFs) as a support material for enhancing the electrocatalytic oxygen evolution reaction (OER). The integration of HgS and CuO into the MOF framework aims to leverage the unique electronic and structural properties of both the nanoparticles and the MOFs to improve catalytic performance. Metal-organic frameworks (MOFs), particularly ZIF-67, are investigated for their potential to catalyze water-splitting reactions due to their high porosity and large specific surface areas. The strategic incorporation of HgS and CuO into ZIF-67 significantly enhances its electrocatalytic properties, resulting in remarkable performance metrics: a low overpotential of 246 mV at 10 mA/cm2, a Tafel slope of 123 mV/dec, an expanded electrochemical active surface area (ECSA) of 23.56 cm2, and a reduced charge transfer resistance of 34.86 Ω. This integration enhances porosity and increases active surface area, which is crucial for improved catalytic performance. This investigation introduces an innovative methodology for fabricating highly efficient electrocatalysts, positioning HgS/CuO/ZIF-67 as a promising candidate for oxygen evolution reactions in alkaline media. The findings highlight the potential of this novel nanocomposite in future clean energy applications, particularly in the realm of water-splitting technologies.

Ternary PdIrNi Telluride Amorphous Mesoporous Nanocatalyst for Efficient Electro-Oxidation of Ethylene Glycol

The development of efficient electrocatalysts for the complete oxidation of ethylene glycol (EG) is crucial for enhancing the practicality of direct EG fuel cells (DEGFCs). However, significant challenges persist in developing highly active Pd-based catalytic electrodes. In this work, PdIrNi ternary telluride nanospheres (PdIrNiTe-MNSPs) with mesoporous morphology and an amorphous structure were successfully synthesized and applied in electrocatalytic EG oxidation reaction. Brunauer–Emmett–Teller analysis revealed typical mesoporous characteristics, with a surface area of 8.33 m2·g−1 and a total pore volume of 0.055 cm3·g−1, respectively. Transmission electron microscopy characterization showed that the outer layer of PdIrNiTe-MNSPs is entirely amorphous in structure. Electrochemical tests demonstrated that PdIrNiTe-MNSPs exhibit enhanced electrocatalytic specific activity (16.75 mA·cm−2) and mass activity (1372.22 mA·mg−1) for EG oxidation reaction (EGOR), achieving 3.17 and 2.09 times higher than commercial Pd/C, which can be attributed to its unique nanoarchitecture and optimized electron configuration. In situ spectroscopy revealed that with the incorporation of IrNi, PdIrNiTe-MNSPs facilitate C-C bond cleavage of EG, achieving a higher selectivity (≈93%) in oxidizing EG to C1 products, while PdTe-MNSPs demonstrated higher selectivity for glycolic acid in EGOR. Taken together, this work provides new insights into the application of Pd-based telluride nanomaterials in electrocatalysis for EGOR.

Electrochemical Hydrogen Evolution with Metal-Organic Framework-Derived Catalysts: Strategies for d-Band Modulation by Electronic Structure Modification.

The effective use of metal-organic framework (MOF)-based materials in the electrocatalytic hydrogen evolution reaction (HER) relies on the understanding of their structural and electronic properties. While the structure and morphology of MOF-derived catalysts significantly impact HER activity, tuning the d-band structure through electronic structure modulation has emerged as a key factor in optimizing catalytic performance. Techniques such as composition tuning, heteroatom doping, surface modification, and interface engineering were found to be effective methods for manipulating the electronic configuration and, in turn, modulating the d-band. This review systematically explores the design strategies for MOF-derived catalysts by focusing on electronic structure modulation. It provides a detailed discussion of the various methods - used to modulate the electronic structure. Furthermore, the review establishes the relationship between d-band tuning, Gibbs free energy, and electronic structure modulation, supported by both spectroscopic and theoretical evidences.

Vibrational Property Tuning of MXenes Revealed by Sublattice N Reactivity in Polar and Nonpolar Solvents.

MXenes, a family of two-dimensional (2D) materials based on transition metal carbides and nitrides, have desirable properties, such as high conductivity, high surface area, and tunable surface groups, for electrocatalysis. Nitride MXenes, in particular, have shown excellent electrocatalytic performance for the nitrogen and oxygen reduction reactions, but a fundamental understanding of how their structures evolve during electrocatalysis remains unknown. Equally important and yet unknown is the effect of the reactivity of the lattice nitrogen on the vibrational behavior of nitride MXenes and the resulting implications in electrocatalysis. Here, we investigate the reactivity of lattice nitrogen and the vibrational properties of titanium nitride MXenes in relevant electrocatalytic solvents using confocal Raman spectroscopy. We found that the vibrational modes of titanium nitride MXenes are attenuated in polar solvents, which is revealed through the alteration of the Raman scattering in solvents. Contrary to polar solvents, the vibrational modes remain unchanged in nonpolar solvents like hydrocarbons due to the inactivity of the lattice nitrogen. We found that this behavior is unique to nitrides because the Raman characteristics of carbides and sulfides are unaffected by the solvent types. However, the inclusion of nitrogen into the carbide structure does exhibit Raman-solvent behavior similar to that of nitrides, suggesting that replacing carbon with nitrogen affects MXene-light interactions. We demonstrated a proof-of-concept utilizing lattice nitrogen reactivity to enhance the electrocatalytic nitrogen reduction reaction for ammonia production. In summary, we elucidate the vibrational properties of nitride MXenes in solvents and demonstrate the tunability of MXene vibrational properties via lattice atom substitution, which in turn can be exploited to advance the applications of MXenes in electrocatalysis.

Charge Transfer Modulation in g-C3N4/CeO2 Composites: Electrocatalytic Oxygen Reduction for H2O2 Production.

The electrocatalytic two-electron oxygen reduction reaction (2e-ORR) represents one of the most prospective avenues for the in situ synthesis of hydrogen peroxide (H2O2). However, the four-electron competition reaction constrains the efficiency of H2O2 synthesis. Therefore, there is an urgent need to develop superior catalysts to facilitate the H2O2 synthesis. In this study, graphite-phase carbon nitride and cerium dioxide composites (g-C3N4/CeO2) with varying CeO2 loadings were prepared with favorable 2e-ORR electrocatalysts. The optimized composite, containing 20 wt % CeO2 (g-C3N4/CeO2-20%) exhibited the highest Faradaic efficiency (FE) of 97% and notable H2O2 yielding of 9.84 mol gcat.-1 h-1 at the potential of 0.3 V (vs RHE) in a 0.1 M KOH electrolyte. Density functional theory calculations revealed that the improvement of the selectivity and yield of H2O2 for the composites were attributed to the charge transfer between g-C3N4 and CeO2, which causes the active site C atom donating electrons to form C+, thereby enhancing the adsorption and desorption of *OOH intermediates. Additionally, the g-C3N4/CeO2-20% composite exhibits excellent 2e-ORR performance in neutral and acidic electrolytes and demonstrates superior capability in electro-Fenton degradation of organic pollutants. This study not only provides new insights into the electrocatalytic mechanism of g-C3N4/CeO2 composites but also demonstrates an effective method for designing 2e-ORR catalysts.

Principles of coordination structure design of single-atom catalysts in electrocatalytic oxygen reduction reaction

Principles of coordination structure design of single-atom catalysts in electrocatalytic oxygen reduction reaction

Bias Dependence of the Transition State of the Hydrogen Evolution Reaction.

The hydrogen evolution reaction (HER) is one of the most prominent electrocatalytic reactions of green energy transition. However, the kinetics across materials and electrolyte pH and the impact of hydrogen coverage at high current densities remain poorly understood. Here, we study the HER kinetics over a large set of nanoparticle catalysts in industrially relevant acidic and alkaline membrane electrode assemblies that are only operated with pure water humidified gases. We discover distinct kinetic fingerprints between the iron triad (Fe, Ni, Co), coinage (Au, Cu, Ag), and platinum group metals (Ir, Pt, Pd, Rh). Importantly, the applied bias changes not only the activation energy (EA) but also the pre-exponential factor (A). We interpret these changes as entropic changes in the interfacial solvent that differ between acid and base and entropic changes on the surface due to a changing hydrogen coverage. Finally, we observe that anions can induce Butler-Volmer behavior for the coinage metals in acid. Our results provide a new foundation to understand HER kinetics and, more broadly, highlight the pressing need to update common understanding of basic concepts in the field of electrocatalysis.

Industrial-level Paired Electrosynthesis of Valuable Chemicals over a High-performance Heterostructural Electrode.

Paired electrosynthetic technology is of significance to realize the co-production of high-added value chemicals. However, exploiting efficient bifunctional electrocatalyst of the concurrent electrocatalysis to achieve the industrial-level performance is still challenging. Herein, an amorphous Co2P@MoOx heterostructure is rationally designed by in-situ electrodeposition strategy, which is acted as excellent bifunctional catalysts for the electrocatalytic nitrite reduction reaction (NO2RR) and glycerol oxidation reaction (GOR). The membrane-electrode assembly (MEA) electrolyzer realizes a low voltage of 1.30 V, robust stability over 200 h at 100 mA cm-2, high Faraday efficiencies and yield of NH3 (above 95%, 49.7 mg h-1 cm-2) and formate (above 95%, 152.3 mg h-1 cm-2) at industrial-level current density of 500 mA cm-2. In-situ spectroscopy studies have shown that high-valence CoOOH is the main active material of GOR, and the main catalytic conversion pathway of NO2RR involves key *NH2OH reaction intermediates. In addition, theoretical calculations confirm that the Co2P@MoOx heterostructure has strong interfacial electronic interaction and optimized reaction energy barriers, which endows its intrinsically high electrocatalytic activity for the co-electrosynthesis of NH3 and formate.

Industrial‐level Paired Electrosynthesis of Valuable Chemicals over a High‐performance Heterostructural Electrode

Paired electrosynthetic technology is of significance to realize the co‐production of high‐added value chemicals. However, exploiting efficient bifunctional electrocatalyst of the concurrent electrocatalysis to achieve the industrial‐level performance is still challenging. Herein, an amorphous Co2P@MoOx heterostructure is rationally designed by in‐situ electrodeposition strategy, which is acted as excellent bifunctional catalysts for the electrocatalytic nitrite reduction reaction (NO2RR) and glycerol oxidation reaction (GOR). The membrane‐electrode assembly (MEA) electrolyzer realizes a low voltage of 1.30 V, robust stability over 200 h at 100 mA cm‐2, high Faraday efficiencies and yield of NH3 (above 95%, 49.7 mg h‐1 cm‐2) and formate (above 95%, 152.3 mg h‐1 cm‐2) at industrial‐level current density of 500 mA cm‐2. In‐situ spectroscopy studies have shown that high‐valence CoOOH is the main active material of GOR, and the main catalytic conversion pathway of NO2RR involves key *NH2OH reaction intermediates. In addition, theoretical calculations confirm that the Co2P@MoOx heterostructure has strong interfacial electronic interaction and optimized reaction energy barriers, which endows its intrinsically high electrocatalytic activity for the co‐electrosynthesis of NH3 and formate.

Toward Explicit Solvation for Simulations of Electrocatalytic Reactions: AIMD for pKa and Redox Potentials of Transition Metal Compounds and Catalyst Models.

In this work, we study the possibility to extend electronic structure simulations for electrocatalysis by explicit solvation models. In previous work, we proposed a simulation scheme that explicitly includes the effects of pH and electrochemical potential in density functional theory (DFT) simulations with implicit solvation. Based on calculations of protonation and oxidation reactions, the pH and electrochemical potential can be included given appropriate reference values. In this work, we compute the pKa values and oxidation potentials for a series of transition metal aquo complexes and compare the results including implicit, explicit static and explicit dynamic (AIMD) models for the aqueous solvent and compare vs experimental pKa and redox potential data. This allows the construction of a pKa/redox potential scale that can in principle be extrapolated to the simulation of other transition metal-based materials. An explicit dynamic solvent model is then proposed and applied to a model system for iridium oxide-based catalysts for the oxygen evolution reaction. We outline the advantages and disadvantages of the different approaches and demonstrate that, at the expense of a larger computational effort, the microsolvation environment of a given model can be described in a robust way using a limited amount of solvent molecules and AIMD. Especially for reactions in which water is solvent and reactant like the oxygen evolution reaction (OER) or oxygen reduction reaction (ORR), this model provides a more detailed and complete description that can be exploited in mechanistic studies.

Substrate Engineering of Single Atom Catalysts Enabled Next-Generation Electrocatalysis to Power a More Sustainable Future

Single-atom catalysts (SACs) are presently recognized as cutting-edge heterogeneous catalysts for electrochemical applications because of their nearly 100% utilization of active metal atoms and having well-defined active sites. In this regard, SACs are considered renowned electrocatalysts for electrocatalytic O2 reduction reaction (ORR), O2 evolution reaction (OER), H2 evolution reaction (HER), water splitting, CO2 reduction reaction (CO2RR), N2 reduction reaction (NRR), and NO3 reduction reaction (NO3RR). Extensive research has been carried out to strategically design and produce affordable, efficient, and durable SACs for electrocatalysis. Meanwhile, persistent efforts have been conducted to acquire insights into the structural and electronic properties of SACs when stabilized on an adequate matrix for electrocatalytic reactions. We present a thorough and evaluative review that begins with a comprehensive analysis of the various substrates, such as carbon substrate, metal oxide substrate, alloy-based substrate, transition metal dichalcogenides (TMD)-based substrate, MXenes substrate, and MOF substrate, along with their metal-support interaction (MSI), stabilization, and coordination environment (CE), highlighting the notable contribution of support, which influences their electrocatalytic performance. We discuss a variety of synthetic methods, including bottom-up strategies like impregnation, pyrolysis, ion exchange, atomic layer deposition (ALD), and electrochemical deposition, as well as top-down strategies like host-guest, atom trapping, ball milling, chemical vapor deposition (CVD), and abrasion. We also discuss how diverse regulatory strategies, including morphology and vacancy engineering, heteroatom doping, facet engineering, and crystallinity management, affect various electrocatalytic reactions in these supports. Lastly, the pivotal obstacles and opportunities in using SACs for electrocatalytic processes, along with fundamental principles for developing fascinating SACs with outstanding reactivity, selectivity, and stability, have been highlighted.

Electrosynthesis of NH3 from NO with ampere-level current density in a pressurized electrolyzer

Electrocatalytic NO reduction reaction (NORR) offers a promising route for sustainable NH3 synthesis along with removal of NO pollutant. However, it remains a great challenge to accomplish both high NH3 production rate and long duration to satisfy industrial application demands. Here, we report an in situ-formed hierarchical porous Cu nanowire array monolithic electrode ensembled in a pressurized electrolyzer to regulate NORR reaction kinetics and thermodynamics, which delivers an industrial-level NH3 partial current density of 1007 mA cm–2 with Faradaic efficiency of 96.1% and remains stable at 1000 mA cm–2 for 100 hours. Integrating the Cu nanowire array monolithic electrode with pressurized electrolyzer boosts the NH3 production rate to 10.5 mmol h–1 cm–2, which is over tenfold that using commercial Cu foam at 1 atm. The NORR performance can be attributed to the promoted NO mass transfer to the enriched Cu surface, which could increase the NO coverage on Cu and then destabilize adsorbed NO and weaken hydrogen adsorption, thereby facilitating NO hydrogenation to NH3 while suppressing the competing hydrogen evolution.

Rh, Co, and N-doped titanium mesh-based carbon nanosheet arrays for enhanced nitrite reduction reaction and ammonia generation

The electrocatalytic transformation of nitrite pollutants into valuable ammonia is crucial for the nitrogen cycle. However, the complex multi-reaction process necessitates the development of highly efficient and selective electrocatalysts. This study focuses on the creation of Rh-doped Co@NC anchored on a titanium mesh as an electrocatalyst to enhance the electrocatalytic nitrite reduction reaction (eNO2RR) for NH3 synthesis. By doping a trace amount of Rh within zeolitic imidazolate framework-67 nanosheets and subsequently pyrolyzing the material, uniformly distributed Rh and Co nanoparticles are anchored onto N-functionalized porous carbon nanosheet arrays. Consequently, the three-dimensional electrode enhances mass and electron transfer while providing abundant surface-exposed active sites for NH3 generation through eNO2RR. The Rh0.6 wt%–Co@NC/TM electrocatalyst, with a minimal Rh loading of 0.6 wt%, exhibits the highest Faradaic efficiency of 98.8 ± 0.7 % at −0.3 V, along with an NH3 yield of 1777.1 ± 7.0 μmol h−1 cm−2 at −0.7 V. Additionally, the electrocatalyst demonstrates exceptional durability over 20 consecutive cycles and remarkable environmental adaptability. Extensive experimental studies reveal that the superior performance of Rh0.6 wt%–Co@NC/TM arises from the synergistic catalysis between Co and Rh, which enhances NO2– adsorption and the production of active hydrogen for eNO2RR to NH3 synthesis. This research highlights that Rh incorporation facilitates the kinetics of eNO2RR and offers valuable insights for the development of efficient electrocatalysts towards NH3 synthesis.

Regulation of Ni3S2@NiS Heterostructure Grown on Industrial Nickel Net for Improved Electrocatalytic Hydrogen Evolution

A novel all-in-one catalytic electrode containing a Ni3S2@NiS heterostructure (Ni3S2@NiS/Ni-Net) was in situ synthesized on an industrial nickel net (Ni-Net) using a one-step solvothermal method, in which ethanol was the solvent and thioacetamide was the sulfur source, respectively. The effects of the addition amount of the sulfur source on the composition, morphology, and electronic structure of the Ni3S2@NiS heterostructures and their electrocatalytic hydrogen evolution reaction (HER) activities were investigated. When 2 mmol of sulfur source was introduced, the prepared Ni3S2@NiS/Ni-Net electrode with a nanorod-like structure required overpotentials of 207 and 322 mV to drive the current densities of 100 and 500 mA/cm2, respectively, in 1 M KOH solution, and only needed the overpotential of 429 mV to deliver 1000 mA/cm2. Meanwhile, the Ni3S2@NiS/Ni-Net electrode can operate stably at a high current density of 90 mA/cm2 under harsh alkaline conditions for at least 100 h. The results show that the Ni3S2@NiS/Ni-Net electrode has high activity and stable HER performance at a high current density, which provides a new idea for the development of high-efficiency electrodes for industrial alkaline hydrogen production.

Enhanced Activity and Stability for Electrocatalytic Nitrate Reduction to Ammonia over Low-Coordinated Cobalt.

It is still challenging to develop an effective strategy to simultaneously enhance the activity and stability of electrocatalysts for electrocatalytic nitrate reduction reaction (eNO3RR). Herein, taking metallic cobalt as an example, it is demonstrated that the construction of low-coordinated cobalt nanosheets (L-Co NSs) by H2 plasma etching of electrodeposited cobalt nanosheets (Co NSs) can greatly enhance the activity and stability of metallic cobalt for eNO3RR. Compared with Co NSs, at -0.4V versus RHE, the nitrate removal rate, ammonia partial current density, and ammonia yield are increased by L-Co NSs from 82.14% to 98.57%, from 476 to 683mA cm-2, and from 2.11 to 2.54mmol h-1 cm-2, respectively. In addition, L-Co NSs demonstrate negligible activity decay after 30 cycles of stability test, while the Co NSs show significant activity decline. In situ electrochemical characterizations and theoretical calculations verify that the abundance of Co vacancies in L-Co NSs not only contribute to the optimized electronic structure and enhanced desorption of key intermediate to boost the activity but also facilitate the transformation of Co(OH)2 to Co0 to promote the stability. Furthermore, L-Co NSs exhibit favorable performance in removing nitrate from simulated wastewater and air plasma discharge-electrocatalytic reduction cascade system to produce ammonia.

Modulation of Electrochemical Reactions through External Stimuli: Applications in Oxygen Evolution Reaction and Beyond.

Electrochemical water splitting is a promising method for generating green hydrogen gas, offering a sustainable approach to addressing global energy challenges. However, the sluggish kinetics of the anodic oxygen evolution reaction (OER) poses a great obstacle to its practical application. Recently, increasing attention has been focused on introducing various external stimuli to modify the OER process. Despite significant enhancement in catalytic performance, an in-depth understanding of the origin of superior OER activity contributed by the external stimuli remains elusive, which significantly hinders the further development of highly efficient and durable water electrolyzed devices. Herein, this review systematically summarizes the recent advancements in the understanding of various external stimuli, including photon irradiation, applied magnetic field, and thermal heating, etc., to boost OER activities. In particular, the underlying mechanisms of external stimuli to promote species transfer, modify the electronic structure of electrocatalysts, and accelerate structural reconstruction are highlighted. Additionally, applications of external stimuli in other electrocatalytic reactions are also presented. Finally, several remaining challenges and future opportunities are discussed, providing insights that could further the study of external stimuli in electrocatalytic reactions and support the rational design of highly efficient energy storage and conversion devices.

Electrochemically Driven Selective Olefin Epoxidation by Cobalt-TAML Catalyst.

Epoxides are versatile chemical intermediates that are used in the manufacture of diversified industrial products. For decades, thermochemical conversion has long been employed as the primary synthetic route. However, it has several drawbacks, such as harsh and explosive operating conditions, as well as a significant greenhouse gas emissions problem. In this study, we propose an alternative electrocatalytic epoxidation reaction, using [CoIII(TAML)]- (TAML = tetraamido macrocyclic ligand) as a molecular catalyst. Under ambient conditions, the catalyst selectively epoxidized olefin substrates using water as the oxygen atom source, affording an efficient catalytic epoxidation of olefins with a broad substrate scope. Notably, [CoIII(TAML)]- achieved >60% Faradaic efficiency (FE) with >90% selectivity for cyclohexene epoxidation, which other heterogeneous electrocatalysts have never attained. Electrokinetic studies shed further light on the detailed mechanism of olefin epoxidation, which involved a rate-limiting proton-coupled electron transfer process, forming reactive cobalt oxygen active species embedded in 2e-oxidized TAML. Operando voltammetry-electrospray ionization mass spectrometry (VESI-MS) and electron paramagnetic resonance (EPR) analyses were utilized to identify a cobalt oxygen active intermediate during an electrocatalytic epoxidation by [CoIII(TAML)]-. Our findings offer a new possibility for sustainable chemical feedstock production using electrochemical methods.

An In‐Depth Study of the Fe−Se System at the Nanoscale Reveals Remarkable Results on the Electrocatalytic Oxygen Evolution Reaction

AbstractA catalyst for an electrocatalytic oxygen evolution reaction (OER) is a key component of the large‐scale storage of renewable energy through the conversion of water into oxygen and hydrogen. Iron‐based selenide materials are currently being considered as potential options for electrocatalytic oxygen evolution reaction (OER) because of their, widespread availability, low cost, and outstanding performance. In this study, we employed a thermal decomposition method to synthesize all stable phases of the Fe−Se system, including Fe7Se8, Fe3Se4, FeSe2, and FeSe. Additionally, we slurry‐coated these phases onto a three‐dimensional (3D) nickel foam substrate. The prepared 3D electrodes of Fe7Se8, Fe3Se4, FeSe2, and FeSe exhibit remarkably low overpotentials of 270, 276, 299, and 289 mV at a current density of 50 mA/cm2 for OER. In addition, the catalytic activity for OER is also tested on glassy carbon electrodes to compare its performance with the Ni‐foam 3D substrate. The Fe7Se8 phase in the Fe−Se system exhibits the highest catalytic activity towards OER on both substrates due to variations in the Fe2+/Fe3+ ratio and the presence of Fe vacancies (cation vacancies) within the crystal lattice. Moreover, a faradaic efficiency of 98 % was exhibited by Fe7Se8 for the oxygen evolution reaction (OER).

Size-Controllable High-Entropy Alloys Toward Stable Hydrogen Production at Industrial-Scale Current Densities.

Efficient and stable electrocatalytic hydrogen evolution reaction (HER) at high current densities is highly desirable for industrial-scale hydrogen production, which is yet challenging, because of the electrocatalyst with short lifespans during the acidic HER process. Here, a controllable preparation technique is successfully developed to synthesize PdPtRuRhAu high-entropy alloys (HEAs) of various sizes, within the 3.14nm particles (HEA-3.14) demonstrating exceptional catalytic performance and stable hydrogen production at current densities of -500 and -1000 mA·cm-2 with negligible activity loss over 100h. Theoretical calculations indicate that the bridge adsorption site of Pd-Au serves as an ideal location for HER, with HEA-3.14 possessing the highest proportion of such sites, reaching 18.97%. To further analyze the thermodynamic stability of HEAs, an element-encoding machine learning model is developed from over 300000 preprocessed dataset of HEAs that achieving an impressively low RMSE of 58.6°C and a high R2 value of 0.98. By integrating thermodynamic modeling with machine learning methods, the melting point of the PdPtRuRhAu HEAs at 3.14nm (366°C) is predicted, which aligns well with the results obtained from differential scanning calorimetry tests. This work offers new insights and approaches for designing HEAs that reliably produce hydrogen at high current densities.

Microenvironment engineering by targeted delivery of Ag nanoparticles for boosting electrocatalytic CO2 reduction reaction

Creating and maintaining a favorable microenvironment for electrocatalytic CO2 reduction reaction (eCO2RR) is challenging due to the vigorous interactions with both gas and electrolyte solution during the electrocatalysis. Herein, to boost the performance of eCO2RR, a unique synthetic method that deploys the in situ reduction of precoated precursors is developed to produce activated Ag nanoparticles (NPs) within the gas diffusion layer (GDL), where the thus-obtained Ag NPs-Skeleton can block direct contact between the active Ag sites and electrolyte. Specifically, compared to the conventional surface loading mode in the acidic media, our freestanding and binder free electrode can achieve obvious higher CO selectivity of 94%, CO production rate of 23.3 mol g−1 h−1, single-pass CO2 conversion of 58.6%, and enhanced long-term stability of 8 hours. Our study shows that delivering catalysts within the GDL does not only gain the desired physical protection from GDL skeleton to achieve a superior local microenvironment for more efficient pH-universal eCO2RR, but also manifests the pore structures to effectively address gas accumulation and flood issues.