Electrocatalytic Oxidation Reaction Research Articles

Tailored Ni(OH)2/CuCo/Ni(OH)2 Composite Interfaces for Efficient and Durable Urea Oxidation Reaction.

Electrocatalytic urea oxidation reaction is a promising alternative to water oxidation for more efficient hydrogen production due to its significantly lower thermodynamic potential. However, achieving efficient electrochemical urea oxidation remains a formidable challenge, and development of an improved electrocatalyst with an optimal physicochemical and electronic structure toward urea oxidation is desired. This can be accomplished by designing a tailored two-dimensional composite with an abundance of active sites in a favorable electronic environment. In this study, we demonstrate the fabrication of a self-supported, electrochemically grown metal/mixed metal hydroxide composite interface via a two-step electrodeposition method. Specifically, Ni(OH)2 was electrodeposited on the top of the CuCo layer (Ni(OH)2/CuCo/Ni(OH)2), and the resultant 2D composite structure required 1.333 ± 0.006 V to oxidize urea electrochemically to achieve a current density of 10 mA cm-2, which outperformed the potential required for individual components, Ni(OH)2 and CuCo. The high density of Ni3+ active sites in the composite structure facilitated high electrocatalyst activity and stability. Ni(OH)2/CuCo/Ni(OH)2 was stable for at least 50 h without any noticeable degradation in the activity or alteration of the morphology. As a bifunctional electrocatalyst, the material also exhibited excellent performance for water oxidation with 260 mV overpotential and 50 h stability. In a two-electrode configuration coupled with a NiMo cathode catalyst, the electrolyzer required 1.42 V cell voltage for overall urea splitting. Overall, the engineered Ni(OH)2/CuCo/Ni(OH)2 composite demonstrated exceptional potential as an efficient and stable electrocatalyst for both urea and water oxidation reactions, paving the way for more effective hydrogen production technologies.

Activating Lattice Oxygen by Electrochemical De-Lithiation for Efficient Benzyl Alcohol Oxidation.

Electrocatalytic benzyl alcohol oxidation reaction (EBOR) is a feasible way to produce high-value-added benzaldehyde and benzoic acid. However, the performance of catalyst usually suffers from the high energy barrier for the O─O bonding step resulting in sluggish process. Herein, lattice oxygen activation strategy is proposed by the electrochemical de-lithiation of LiNiO2 to catalyze the EBOR through direct O─O bonding to significantly enhance the EBOR performance. The electrochemical de-lithiation make the charge redistributed in Ni-O portion, leading to the lattice oxygen in LiNiO2 activated, thereby reducing the energy barrier of the O─O coupling step by following lattice oxygen mechanism (LOM). The constructed de-LiNiO2 exhibits excellent EBOR catalytic activity featuring current densities of 100 and 400mAcm-2 at only 1.397 and 1.431V, respectively, outperforming the currently reported analogous electrocatalysts. The formation of high-valence Ni4+ after de-lithiation leads to direct O-O coupling between lattice oxygen in de-LiNiO2 and oxygen-containing intermediates in EBOR, favoring an energetically favorable LOM pathway, thereby enhancing the EBOR performance. This work provides a new strategy to enhance the electrocatalytic activity by changing the reaction mechanism rather than focusing on catalyst design, opening up a new path for the development of advanced biomass oxidation electrocatalysts.

Synergistic Inclusion of Reaction Activator and Reaction Accelerator to Ni-MOF Toward Extra-Ordinary Performance of Urea Oxidation Reaction.

Recently electrochemical urea oxidation reaction (UOR) has emerged as the technology of demand for commercialization of urea-based energy conversion. However, the nascent idea is limited by the energy burden of threshold voltage and the sluggish reaction kinetics involving a six-electron transfer mechanism. Herein, for the first time, the engineering of electrocatalysts are proposed with simultaneous inclusion of UOR activator and UOR accelerator. Nitrogen-doped carbon-decorated Ni-based Metal Organic Framework (MOF)has been synthesized as the base catalyst material. MoO2 and rGO with varied loading have been attached to the MOF to get the desired MoO2/Ni-MOF/rGO heterostructure incorporating defects and crystal strain within the materials. Investigations reveal that the invoked lattice strain and atomic defects promote plenteous Ni3+ active sites. The optimized sample demonstrates extraordinary performance of UOR having the potential value as low as 1.32V versus RHE to reach the current density of 10mAcm-2 and the tafel slope is only 31mVdec-1 reflecting very fast reaction kinetics. Here MoO2 plays the role of UOR activator whereas optimized loading of rGO proliferates the reaction speed. This work, experimentally and theoretically, presents a new insight to enhance electrocatalytic urea oxidation reaction opening an avenue of urea-based energy-harvesting technology.

Non-Noble Metal Catalysts for Electrooxidation of 5-Hydroxymethylfurfural.

2,5-Furandicarboxylic acid (FDCA) is a class of valuable biomass-based platform compounds. The creation of FDCA involves the catalytic oxidation of 5-hydroxymethylfurfural (HMF). As a novel catalytic method, electrocatalysis has been utilized in the 5-hydroxymethylfurfural oxidation reaction (HMFOR). Common noble metal catalysts show catalytic activity, which is limited by price and reaction conditions. Non-noble metal catalyst is known for its environmental friendliness, affordability and high efficiency. The development of energy efficient non-noble metal catalysts plays a crucial role in enhancing the HMFOR process. It can greatly upgrade the demand of industrial production, and has important research significance for electrocatalytic oxidation of HMF. In this paper, the reaction mechanism of HMF undergoes electrocatalytic oxidation to produce FDCA are elaborately summarized. There are two reaction pathways and two oxidation mechanisms of HMFOR discussed deeply. In addition, the speculation on the response of the electrode potential to HMFOR is presented in this paper. The main non-noble metal electrocatalysts currently used are classified and summarized by targeting metal element species. Finally, the paper focus on the mechanistic effects of non-noble metal catalysts in the reaction, and provide the present prospects and challenges in the electrocatalytic oxidation reaction of HMF.

Strengthening CuNiCoMo medium-entropy alloy by tuning local lattice tensile strain and built-in electric field for boosting urea oxidation reaction

Developing high-performance catalysts for electrocatalytic urea oxidation reaction (UOR) is significant in treating urea-rich wastewater but remains a considerable challenge. Herein, CuNiCo-7.8%Mo/CF (7.8% is the Mo atom percentage; CF: copper foam) medium entropy alloy catalyst with moderate local lattice tensile strain and built-in electric field is prepared by solvothermal and calcination methods to obtain the good UOR performance. Besides, the operando electrochemical impedance and quasi-operando Raman spectroscopy proved that CuNiCo-7.8%Mo/CF can favor the direct oxidation reaction in a solution of 1.0M KOH and 0.5M urea. The electrochemical results show that CuNiCo-7.8%Mo/CF has a better UOR activity (E10/500/1000 = 1.27/1.44/1.51V) than other studied samples during the UOR process. Meanwhile, CuNiCo-7.8%Mo/CF can stably work for 100h at 1000mAcm−2. Therefore, herein a CuNiCo-7.8%Mo/CF material is designed for high-efficiency UOR at large current density and it is provided as a feasible method for large-scale treating urea-rich wastewater.

Spatially separated redox active sites over Re-Ni@Ni(OH)2 core-shell structure for enhancing furfural oxidation coupled with hydrogen evolution

The design of bifunctional catalysts with spatially separated active sites holds significance importance in achieving simultaneous electrooxidation and hydrogen evolution reaction (HER). Herein, a core-shell Re-Ni@Ni(OH)2/CC heterostructure is demonstrated for the electrocatalytic furfural oxidation reaction (FOR) coupled with HER. Experimental results and theoretical analyses reveal that Re not only modulates the heterointerface between Re-Ni core and Ni(OH)2 shell, facilitating furfural (FF) adsorption at Ni(OH)2 sites, but also tunes electronic structure of Ni. This leads to a negative shift in the d-band center from Fermi level, effectively weakening hydrogen adsorption at Ni sites in Re-Ni@Ni(OH)2 heterostructure, thereby improving the HER process. As a result, the synthesized Re-Ni@Ni(OH)2/CC exhibits a low cell voltage of 1.40 V @10 mA cm−2 for the FOR||HER. This study highlights the importance of modulating metal’s electronic structure and identifying active sites, which has great potential for improving bifunctional electrocatalytic reactions.

Dual performing PtNi alloys nanosheets for electrocatalytic ammonia oxidation reaction and electrochemical detection of ammonia-nitrogen

The design of high-performance electrocatalysts for the ammonia oxidation reaction and the detection of ammonia-nitrogen has always been paid attention due to the potential benefits in regards to direct ammonia fuel cells and environmental protection. Therefore, in this work, we designed and constructed one self-supported electrode by electrodepositing PtNi alloy nanosheets on a carbon cloth substrate. To obtain high-performance PtNi alloy nanosheets, the ratio of H2PtCl6·6 H2O/Ni(NO3)2·6 H2O and deposition time were controlled. The electrochemical catalytic performances for the ammonia oxidation reaction indicated that the best ratio of H2PtCl6·6 H2O/Ni(NO3)2·6 H2O was 3:1 and the best deposition time was 2000 s, achieving a low onset potential with the value of −0.51 V and a high peak current of 36.57 mA. In addition, the electrochemical detection of ammonia-nitrogen also showed great performances with an outstanding sensitivity of 0.0102 mA µM−1 and a low detection limit with the value of 1.154 µM. Moreover, exceptional selectivity, robust reproducibility, excellent reusability, strong stability, and impressive recovery during the analysis of real sample types such as tap water, lake water, and sea water were observed. Therefore, the work provided one potential electrocatalyst for bifunctional applications involving both the ammonia oxidation reaction and ammonia-nitrogen detection.

Suppression of Structural Heterogeneity in High-Entropy Intermetallics for Electrocatalytic Upgrading of Waste Plastics.

The key to fully realizing the potential of high-entropy alloys (HEAs) lies in balancing their inherent local chemical disordering with the long-range ordering required for electrochemical applications. Herein, we synthesized a distinctive L10-(PtIr)(FeMoBi) high-entropy intermetallics (HEIs) exhibiting nanoscale long-range order and atomic scale short-range disorder via a lattice compensation strategy to mitigate the entropy reduction tendency. The (PtIr)(FeMoBi) catalyst exhibited remarkable activity and selectivity of glycollic acid (GA) production via electrocatalytic waste polymer-derived ethylene glycol oxidation reaction (EGOR). With a mass activity of 5.2 A mgPt-1 and a Faradic efficiency (FE) for GA of 95 %, it outperformed most previously reported electrocatalysts for selective GA production. The lattice-compensation effect promotes the homogeneity of Pt and Fe actives sites, facilitating co-adsorption of EG and OH and reducing the energy barriers for dehydrogenation and OH-combination processes. This approach effectively avoids the formation of low-active sites commonly encountered in HEA solid solutions, offering a promising avenue for exploring the complex interplay between catalytic activity and HEI structures.

Triphenylamine-Substituted Ni(II) Porphyrins for Urea Electro-oxidation.

Porphyrin-based molecular catalysts possess a typical aromatic macrocyclic structure regarding their metal centers and coordination frameworks, allowing for the development of promising electrocatalysts through precise selection of the metal and porphyrin ligand. However, reports on metalloporphyrins as catalysts for the electrocatalytic urea oxidation reaction (UOR) remain scarce. With these considerations in mind, the triphenylamine-Ni(II) porphyrin (NiPor-TPA) was synthesized through the solvothermal approach from 5,10,15,20-tetrakis [4-(diphenylamino)phenyl]porphyrin and nickel(II) acetate in this work. Experimental results reveal that the introduction of Ni species can serve as active sites and activate urea oxidation efficiently, and thus the prepared catalysts deliver better electrocatalytic activity than the metal-free TPA. The NiPor-TPA electrode delivers the lowest potential of 1.34 V versus reversible hydrogen electrode (RHE) at 10 mA cm-2 for UOR with a Tafel slope of 44.6 mV dec-1. This work proposes a new porphyrin-based molecular catalyst for effectively boosting electrocatalytic UOR activity. The π-conjugated macroring structure and the excellent electrocatalytic properties both make NiPor-TPA one of the burgeoning electrocatalytic UORs.

Dynamic Fe-O-Cu induced electronic structure modulation on CuOx electrode for selective electrocatalytic oxidation of glycerol

Electrocatalytic glycerol oxidation reaction to produce high-value organic chemicals has research significance for managing the overproduction of glycerol and handling the energy crisis. Herein, a copper-based self-supporting catalytic electrode with a dynamic Fe-O-Cu optimized coordination (Fe-CuOx/CF) was prepared. The oxygen-bridged asymmetric coordination structure (Fe-O-Cu) optimized the electronic configuration and promoted the formation of the crucial intermediate species. After Fe was embedded in the lattice of copper oxides, a remarkable enhancement in the adsorption capacity of OH- and glycerol was confirmed. As a result, Fe-CuOx/CF exhibited an excellent production capacity of formate, with high faradaic efficiency and selectivity values of 93.65 % and 95.10 %. Concurrent production of formate and high purity hydrogen was achieved in the double-electrode flow electrolyzer. This work provides guiding significance for the optimization of the catalytic coordination and the design of high-efficiency transition metal-based catalysts for electrooxidation of biomass platform molecules.

Bifunctional MoNi4/Nickel Foam Electro-Catalyst for Ultra-Efficient Oxidation of High-Concentration 5-Hydroxymethylfurfural and HER.

The electro-catalytic oxidation of biomass-derived 5-hydroxymethylfurfural (HMF) provides an attractive route to produce 2, 5-furandicarboxylic acid (FDCA) as a substitute for terephthalic acid used in the plastics industry. Herein, we prepared MoNi4 alloy on nickel foam (NF) using a simple hydrothermal method followed by hydrogen reduction. Applied MoNi4/NF as the bifunctional electrodes for the electro-catalytic HMF oxidation reaction (HMFOR) and HER, 98.7 % FDCA yield and 97.3 % Faraday efficiency (FE) can be achieved even with HMF concentration as high as 200 mM. Notably, no obvious deactivation was observed after ten consecutive cycles. In-situ Raman, XANES and EXAFS results show that the nickel species of MoNi4/NF is first oxidized to Ni3+ species under the applied voltage, and after undergoing the electro-catalytic HMFOR, then reduced to Ni2-δ state (with a valence between 0 and +2) due to the electron-donating effect from Mo. MoNi4/NF with more than one electron transfer between Ni3+ and Ni2-δ during the HMFOR enables it to have excellent electro-catalytic oxidation ability toward HMFOR.

Growth Modulation of High-Entropy Alloys for Electrocatalytic Methanol Oxidation Reaction.

High-entropy alloy (HEA) electrocatalysts have exhibited remarkable catalytic performance because of their synergistic interactions among multiple metals. However, the growth mechanism of HEAs remains elusive, primarily due to the constraints imposed by the current synthesis methodologies for HEAs. In this work, an innovative electrodeposition method was developed to fabricate Pt-based nanocomposites (Pt1Bi2Co1Cu1Ni1/CC), comprising HEA nanosheets and carbon cloths (CCs). The reaction system could be effectively monitored by taking samples out from the system during the reaction process, facilitating in-depth insight into the growth mechanism underlying the material formation. In particular, Pt1Bi2Co1Cu1Ni1/CC nanocomposites show superior methanol oxidation reaction (MOR) performance (mass activity up to 5.02 A mgPt-1). Upon structural analysis, the d-band center of Pt1Bi2Co1Cu1Ni1/CC is lower in comparison with that of Pt1Bi2/CC and Pt/CC, demonstrating the formation of a rich-electron structure. Both the uniformity of HEAs and the carbon-supported effect could provide additional active sites. These findings suggest that the strong electronic interaction within HEAs and additional active sites can effectively modulate the catalytic structure of Pt, which benefits the enhanced CO tolerance and MOR performance.

Utilizing cationic vacancies to enhance nickel-cobalt layered double hydroxides for efficient electrocatalytic urea oxidation reaction

Electrocatalytic urea oxidation reaction (UOR) is a promising approach for urea-rich wastewater splitting, which benefits for reducing energy consumption in hydrogen production accompanying environmental protection and sustainable energy development. To address the limitations posed by the self-oxidation of nickel-based catalysts on the activity of UOR, we here developed a NiCo LDH nanosheet catalyst with abundant Ni vacancies to initiate the UOR process prior to nickel oxidation. Electrochemical impedance spectroscopy and In-situ spectroscopic characterizations confirm that the UOR process primarily occurs on the surface of the catalyst, rather than being driven by nickel oxidation products. The favorable electronic structure modulation induced by Ni vacancies makes the catalyst more energetically favorable for the UOR compared to nickel self-oxidation. The catalyst exhibits excellent UOR activity, only requiring 1.27 V vs. RHE at 10 mA cm−2 and 1.34 V vs. RHE at 100 mA cm−2, with no significant decay observed after over 120 h of operation. Furthermore, it can function as a bifunctional catalyst, requiring only 1.66 V to achieve 100 mA cm−2 for the UOR||HER system. This study expands the pathway for the application of cationic vacancies in UOR.

Empowering Tri-Functional Palladium's Catalytic Activity and Durability in Electrocatalytic Formic Acid Oxidation Reaction via Innovative Self-Caging and Alloying Strategies.

Direct formic acid fuel cells (DFAFCs) stand out for portable electronic devices owing to their ease of handling, abundant fuel availability, and high theoretical open circuit potential. However, the practical application of DFAFCs is hindered by the unsatisfactory performance of electrocatalysts for the sluggish anodic formic acid oxidation reaction (FAOR). Palladium (Pd) based nanomaterials have shown promise for FAOR due to their highly selective reaction mechanism, but maintaining high electrocatalytic durability remains challenging. In this study, a novel Pd-based electrocatalyst (UiO-Pd-E) is reported with exceptional durability and activity for FAOR, which can be attributed to the Pd nanoparticles encapsulated within a carbon framework where concurrent chemical alloying of Pd and Zr occurs. Further, the UiO-Pd-E demonstrates noteworthy multifunctionality in various electrochemical reactions including electrocatalytic ethanol oxidation reaction (EOR) and oxygen reduction reaction (ORR) in addition to the FAOR, highlighting its practical potentials.

Regulating the electronic structure of nickel phosphides via interface engineering and molybdenum doping boosts benzyl alcohol oxidation coupled with hydrogen production

Coupling the electrocatalytic benzyl alcohol oxidation reaction (BAOR) with hydrogen evolution reaction (HER) presents a favorable energy conversion method. However, the development of highly efficient bifunctional electrocatalysts poses significant challenges. In this study, a Mo doped biphasic Ni2P-Ni12P5 heterostructure (Mo-Ni2P/Ni12P5@NF) has been developed to serve as the efficient bifunctional electrocatalyst. The Mo-Ni2P/Ni12P5@NF resulted in exceptional activities for both the BAOR and HER. The electrolyzer cell using Mo-Ni2P/Ni12P5@NF as anode and cathode operates at an impressively low cell voltage of merely 1.38 V to achieve the current density of 10 mA cm−2 in a benzyl alcohol-containing aqueous solution. Experimental results and density functional theory (DFT) calculations indicate that the introduction of Mo can significantly modulate the electronic structure of Ni-based phosphide catalysts and adjust for the d-band center of the active Ni sites. This modulation significantly optimizes the adsorption capabilities for both benzyl alkoxide (Ph-CH2O-) and the H* intermediates on Mo-Ni2P/Ni12P5@NF, thereby increasing electrocatalytic activity toward BAOR and HER respectively. Our work offers a valuable insight into designing bifunctional electrocatalysts and highlights the potential of Mo doping systems to produce hydrogen and value-added products efficiently.

Construction of Multiphase Concave Tetrahedral PdInMo Nanocatalyst for Enhanced Alcohol Oxidation

AbstractHeterogeneous palladium‐based catalysts show excellent catalytic properties for electrocatalytic oxidation of alcohols, but the construction of such heterogeneous catalysts is a challenge. Here, a multiphase tetrahedral PdInMo nanocatalyst is prepared by a one‐pot reaction method. And the multiphase tetrahedral PdInMo nanocatalyst consists of a face‐centered cubic structure and an intermetallic structure. Due to the oxygen affinity of indium and molybdenum atoms, the interface defects of internal multiphase structure, and intermetallic structure, the multiphase concave tetrahedral PdInMo nanocatalyst shows enhanced catalytic efficiency in the electrocatalytic oxidation reaction of methanol and ethanol. Compared with commercial Pd/C catalysts, PdIn0.117Mo0.037 nanocatalyst has the best mass activity and specific activity. In electrocatalysis of methanol oxidation, the mass activity (2205.57 mA mgPd−1) and specific activity (6.67 mA cm−2) are 4.81 and 3.40 times than that of a commercial Pd/C nanocatalyst (458.5 mA mgPd−1, 1.96 mA cm−2), respectively. In the electrocatalysis of ethanol oxidation, the mass activity (2668.49 mA mgPd−1) and specific activity (8.11 mA cm−2) are 4.06 and 3.14 times than that of the commercial Pd/C nanocatalyst (655.83 mA mgPd−1, 2.58 mA cm−2), respectively. This study provides a reference for the design of highly efficient palladium catalysts for alcohol oxidation.

Cluster-Cation Pairs Mediated Assembly of Subnanometer Polyoxometalates Superstructures.

Superstructures assembled by subnanometer polyoxometalate (POM) clusters are interesting for their attractive structures and excellent properties. However, the complex interactions between clusters and cations make it challenging to control the assembly of POM clusters at the subnanometer scale. Here, 20 cluster-assembled superstructures built by two types of MP2W17O61 (M = La-Lu) clusters are successfully synthesized. The precise structures and configurations of the subnanostructures, including nanowires, tetragonal nanosheets, and rectangular nanosheets, are characterized and presented. Molecular dynamics (MD) simulations reveal that the difference in interactions of POM clusters and cations leads to the formation of distinct superstructures. Two mechanisms of superstructure formation are proposed. Furthermore, the EuP2W17 nanosheet behaves with a high Faradaic efficiency of 90.2% and selectivity of 87.3% for glycolic acid in the electrocatalytic ethylene glycol oxidation reaction, which is much higher than that of isolated cluster components. This work connects the cluster topologies and cluster-cation pairs to the superstructures of cluster assemblies, providing general guidelines for the supramolecular self-assembly of POM clusters.

Preparation of rGO/CAU-10 anchored PdPbBi composites and their electrocatalytic ethylene glycol properties

An effective method to improve the catalytic performance of electrocatalytic alcohol oxidation by establishing strong interfacial interactions through novel carrier materials and polymetallic alloys. In this paper, novel polyhedral metal–organic framework Al-based [Al(OH)(mBDC)] (CAU-10) composites with PdPbBi trimetallic particles embedded in folded graphene oxide (rGO) modified by a simple hydrothermal reaction were prepared and applied to the electrocatalytic oxidation reaction of ethylene glycol. The results of electrochemical tests showed that the trimetallic catalysts exhibited excellent electrocatalytic activity compared to commercial Pd/C. In particular, PdPbBi@rGO/CAU-10 has the highest peak current density of 241.82 mA cm−2, which is 8.97 times higher than that of Pd/C (26.92 mA cm−2), and the largest electrochemical active area (ECSA) value of 88.12 mA cm−2, which is 2.40 times higher than that of Pd/C (36.75 mA cm−2). This outstanding electrocatalytic activity is mainly attributed to the polyhedral structure of CAU-10 composite carriers and the abundance of oxygen-containing atoms, which is conducive to the homogeneous loading of metals, at the same time, the strong electronic effect between Pd, Pb and Bi and the abundance of oxygen-containing species provide significant enhancement of electrocatalytic activity and stability, which provides an important reference for the development of electrocatalysts for ethylene glycol fuel cells.

Leveraging Soft Acid-Base Interactions Alters the Pathway for Electrochemical Nitrogen Oxidation to Nitrate with High Faradaic Efficiency.

Electrocatalytic nitrogen oxidation reaction (N2OR) offers a sustainable alternative to the conventional methods such as the Haber-Bosch and Ostwald oxidation processes for converting nitrogen (N2) into high-value-added nitrate (NO3 -) under mild conditions. However, the concurrent oxygen evolution reaction (OER) and inefficient N2 absorption/activation led to slow N2OR kinetics, resulting in low Faradaic efficiencies and NO3 - yield rates. This study explored oxygen-vacancy induced tin oxide (SnO2-Ov) as an efficient N2OR electrocatalyst, achieving an impressive Faradaic efficiency (FE) of 54.2% and a notable NO3 - yield rate (22.05µg h-1 mgcat -1) at 1.7V versus reversible hydrogen electrode (RHE) in 0.1m Na2SO4. Experimental results indicate that SnO2-Ov possesses substantially more oxygen vacancies than SnO2, correlating with enhanced N2OR performance. Computational findings suggest that the superior performance of SnO2-Ov at a relatively low overpotential is due to reduced thermodynamic barrier for the oxidation of *N2 to *N2OH during the rate-determining step, making this step energetically favorable than the oxygen adsorption step for OER. This work demonstrates the feasibility of ambient nitrate synthesis on the soft acidic Sn active site and introduces a new approach for rational catalyst design.

Novel electrocatalyst with abundant oxygen vacancies enabling efficient two-electron water oxidation reaction for H2O2 synthesis

In the realm of electrocatalytic two-electron water oxidation reaction, the quest for efficient and selective catalysts poses a significant challenge in balancing productivity and activity, hindering the decentralized generation of hydrogen peroxide (H2O2) through electrochemical means. Addressing this hurdle, our study introduces a novel approach to crafting an effective and stable electrocatalyst for the two-electron water oxidation reaction (2e-WOR). Through the synthesis of magnesium stannite tungstate from a mixture of MgSnO3 and WO3, the engineer of a material with abundant oxygen vacancies is crucial for catalytic activity. This catalyst demonstrates exceptional performance, ascribed to its distinctive oxygen vacancies proximal to the active center Sn and electronic modulation by tungsten. Notably, Mg1-xSnWO6-x700 exhibits a remarkably low overpotential of 70 mV at 10 mA cm−2, coupled with a high faradic efficiency of 84 % for 2e- WOR at 2.6 V vs. RHE, maintaining consistent performance over 35 h. Furthermore, the formation of oxygen vacancies and the associated electronic transfer underscore the novelty and promise of our material in advancing the field of two-electron WOR. In sum, our electrocatalyst presents a cost-efficient and selective solution for water oxidation, offering potential avenues for enhancing H2O2 production.