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Various electrocatalysts are extensively examined for their ability to selectively produce desired products by electrochemical CO2 reduction reaction (CO2RR). However, an efficient CO2RR electrocatalyst doesn't ensure an effective co‐catalyst on the semiconductor surface for photoelectrochemical CO2RR. Herein, Bi2S3 nanorods are synthesized and electrochemically reduced to Bi nanoplates that adhere to the substrates for application in the electrochemical and photoelectrochemical CO2RR. Compared with commercial‐Bi, the Bi2S3‐derived Bi (S‐Bi) nanoplates on carbon paper exhibit superior electrocatalytic activity and selectivity for formate (HCOO−) in the electrochemical CO2RR, achieving a Faradaic efficiency exceeding 93%, with minimal H2 production over a wide potential range. This highly selective S‐Bi catalyst is being employed on the Si photocathode to investigate the behavior of electrocatalysts during photoelectrochemical CO2RR. The strong adhesion of the S‐Bi nanoplates to the Si nanowire substrate and their unique catalytic properties afford exceptional activity and selectivity for HCOO− under simulated solar irradiation. The selectivity observed in electrochemical CO2RR using the S‐Bi catalyst correlates with that seen in the photoelectrochemical CO2RR system. Combined pulsed potential methods and theoretical analyses reveal stabilization of the OCHO* intermediate on the S‐Bi catalyst under specific conditions, which is critical for developing efficient catalysts for CO2‐to‐HCOO− conversion. [ABSTRACT FROM AUTHOR]

NiFe2O4 material is grown on carbon paper (CP) with the hydrothermal method for use as electrocatalysts in an alkaline electrolyzer. NiFe2O4 material is used as the anode and cathode catalysts (named NiFe(+)/NiFe(−) hereafter). The results are compared with those obtained using CP/NiFe as the anode and CP/Ru as the cathode (named NiFe)(+)/Ru(−) hereafter). During cell operation with NiFe(+)/Ru(−), the current density reaches 500 mA/cm2 at a cell voltage of 1.79 V, with a specific energy consumption of 4.9 kWh/m3 and an energy efficiency of 66.2%. In comparison, for NiFe(+)/NiFe(−), the current density reaches 500 mA/cm2 at a cell voltage of 2.23 V, with a specific energy consumption of 5.7 kWh/m3 and an energy efficiency of 56.6%. The Faradaic efficiency is 96–99%. With the current density fixed at 400 mA/cm2, after performing a test for 150 h, the cell voltage with NiFe(+)/Ru(−) increases by 0.167 V, whereas that with NiFe(+)/NiFe(−) decreases by only 0.010 V. Good, long-term stability is demonstrated. [ABSTRACT FROM AUTHOR]

Integrating more active components into a catalyst material could facilitate the development of multifunctional electrocatalysts for energy conversion and storage applications. In this study, we developed a multifunctional electrocatalyst, namely, Pd alloyed with Co-Fe deposited on N-doped mesoporous carbon derived from tissue paper (Pd@Co-Fe/N-TDC). The synergism in Pd@Co-Fe/N-TDC, stemming from the interatomic alloy between Pd and Co-Fe, N-doped mesoporous carbon with defective surfaces, distribution of polyhedral Pd nanoparticles, and strong metal-support interfacial interaction, resulted in significantly high electrocatalytic performance for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Pd@Co-Fe/N-TDC was found to be an efficient bifunctional oxygen electrocatalyst, and this was evidenced by a high onset potential (1.01 V) and kinetic current density (2.6 mA/cm2) for the ORR and by a low overpotential (296 mV) and a low Tafel slope value (38 mV/dec) for the OER, along with a small Δ E of 736 mV. The catalyst also exhibited high durability for both ORR and OER, even after 10000 and 5000 cycles, respectively. Theoretical assessment provides an insight into the synergism of active metal sites in Pd@Co-Fe/N-TDC, which showed its potential for use as a non-Pt electrocatalyst for energy applications. [ABSTRACT FROM AUTHOR]

Metal nanoparticles have extraordinary properties, but their integration into mesostructures has been challenging. Producing uniformly dispersed nanoparticles attached to substrates in industrial quantities is difficult. Herein, a "plasmashock" method was developed to synthesize metal nanoparticles anchored on different types of carbonaceous substrates using liquid salt solution precursors. These self-supporting, nanoparticle-loaded carbon fabrics are mechanically robust and have been tested as antibacterial substrates and electrocatalysts for reducing carbon dioxide and nitrite. A piece of silver–carbon nanotube paper with a silver loading of ~0.13 mg cm−2 treated after a few-second plasmashock presents good antibacterial and electrocatalytic properties in wastewater, even after 20 bactericidal immersion cycles, due to the strong bonding of the nanoparticles to the substrate. The results prove the effectiveness of this plasmashock method in creating free-standing functional composite films or membranes. A "plasmashock" method was developed to synthesize metal nanoparticles anchored on different kinds of carbonaceous substrates using liquid salt solution precursors. These self-supporting, nanoparticles-loaded carbon fabrics are mechanically robust and tested as antibacterial substrate and electrocatalysts for reducing carbon dioxide and nitrite. [ABSTRACT FROM AUTHOR]

Carbon-based single-atom catalysts, a promising candidate in electrocatalysis, offer insights into electron-donating effects of metal center on adjacent atoms. Herein, we present a practical strategy to rationally design a model catalyst with a single zinc (Zn) atom coordinated with nitrogen and sulfur atoms in a multilevel carbon matrix. The Zn site exhibits an atomic interface configuration of ZnN4S1, where Zn's electron injection effect enables thermal-neutral hydrogen adsorption on neighboring atoms, pushing the activity boundaries of carbon electrocatalysts toward electrochemical hydrogen evolution to an unprecedented level. Experimental and theoretical analyses confirm the low-barrier Volmer-Tafel mechanism of proton reduction, while the multishell hollow structures facilitate the hydrogen evolution even at high current intensities. This work provides insights for understanding the actual active species during hydrogen evolution reaction and paves the way for designing high-performance electrocatalysts. [ABSTRACT FROM AUTHOR]

Trillion of cigarette butts are annually littered without being recycled. This work aims at valorizing the whole cigarette butts and their components (paper, filter and tobacco) into Fe‐Nx‐C electrocatalysts for oxygen reduction reaction (ORR) in acid and alkaline media. The pristine wastes were pyrolyzed at 450 °C, activated with KOH at 700 °C, blended with iron phthalocyanine (FePc) precursor, and heat‐treated at 600 °C to produce a robust Fe‐Nx‐C material with ORR active units. The effect of the cigarette components on the final electrocatalytic activity was evaluated by thoroughly investigating the surface chemistry with XPS. The electrocatalysts displayed similar results among the different components in both media due to comparable surface chemistry, especially concerning the nitrogen functional groups. The highest performance was obtained in alkaline where the electrocatalysts from whole cigarettes and paper (CIGF_450 and CIGPF_450) showed an E1/2 of 0.89 V vs RHE, slightly larger than that of Pt/C with 40 wt % of Pt, which encouraged to replace Pt‐based electrocatalysts in alkaline fuel cells. [ABSTRACT FROM AUTHOR]

The electrocatalytic oxidation of glycerol by metal electrocatalysts is an effective method of low-energy-input hydrogen production in membrane reactors in alkaline conditions. The aim of the present study is to examine the proof of concept for the gamma-radiolysis-assisted direct growth of monometallic gold and bimetallic gold–silver nanostructured particles. We revised the gamma radiolysis procedure to generate free-standing Au and Au-Ag nano- and micro-structured particles onto a gas diffusion electrode by the immersion of the substrate in the reaction mixture. The metal particles were synthesized by radiolysis on a flat carbon paper in the presence of capping agents. We have integrated different methods (SEM, EDX, XPS, XRD, ICP-OES, CV, and EIS) to examine in detail the as-synthesized materials and interrogate their electrocatalytic efficiency for glycerol oxidation under baseline conditions to establish a structure–performance relationship. The developed strategy can be easily extended to the synthesis by radiolysis of other types of ready-to-use metal electrocatalysts as advanced electrode materials for heterogeneous catalysis. [ABSTRACT FROM AUTHOR]

The strategic manipulation of the interaction between a central metal atom and its coordinating environment in single-atom catalysts (SACs) is crucial for catalyzing the CO2 reduction reaction (CO2RR). However, it remains a major challenge. While density-functional theory calculations serve as a powerful tool for catalyst screening, their time-consuming nature poses limitations. This paper presents a machine learning (ML) model based on easily accessible intrinsic descriptors to enable rapid, cost-effective, and high-throughput screening of efficient SACs in complex systems. Our ML model comprehensively captures the influences of interactions between 3 and 5d metal centers and 8 C, N-based coordination environments on CO2RR activity and selectivity. We reveal the electronic origin of the different activity trends observed in early and late transition metals during coordination with N atoms. The extreme gradient boosting regression model shows optimal performance in predicting binding energy and limiting potential for both HCOOH and CO production. We confirm that the product of the electronegativity and the valence electron number of metals, the radius of metals, and the average electronegativity of neighboring coordination atoms are the critical intrinsic factors determining CO2RR activity. Our developed ML models successfully predict several high-performance SACs beyond the existing database, demonstrating their potential applicability to other systems. This work provides insights into the low-cost and rational design of high-performance SACs. [ABSTRACT FROM AUTHOR]

The design of efficient and cost-effective electrocatalysts with steady capability has attracted much attention in the field of water splitting in recent years. In this paper, Ni2−xCoxP/CNFs (x = 0, 0.67, 1, 1.33 and 2), where the ultrafine Ni2−xCoxP nanoparticles are encapsulated in carbon nanofibers, are synthesized using a facile electrospinning method followed by thermal treatment. The space confinement by the carbon matrix with a high length-to-diameter ratio (>1000) and excellent conductivity produces ultrafine Ni2−xCoxP with abundant active sites. Moreover, engineering of Ni2−xCoxP/CNFs can induce electronic modulation and consequently optimize the adsorption of H on the electrocatalyst surface to promote HER performance, as well as to reduce the energy barrier of the potential-limiting step. The optimal Ni2−xCoxP/CNFs exhibit superior electrocatalytic performance with low overpotentials of about 271 mV for OER and about 118.76 mV for HER at 10 mA cm−2 with excellent long-term durability in 1.0 M KOH solutions, performing as one of the best non-noble-metal electrocatalysts so far. Furthermore, the two-electrode electrolyser delivers a high efficiency and remarkable long-term durability for overall water splitting. This work provides new insights into the development of nanofiber-structured electrocatalysts. [ABSTRACT FROM AUTHOR]

Microbial fuel cells (MFCs) are sustainable energy recovery systems because they use organic waste as biofuel. Using critical raw materials (CRMs), like platinum-group metals, at the cathode side threatens MFC technology's sustainability and raises costs. By developing an efficient electrode design for MFC performance enhancement, CRM-based cathodic catalysts should be replaced with CRM-free materials. This work proposes developing and optimizing iron-based air cathodes for enhancing oxygen reduction in MFCs. By subjecting iron phthalocyanine and carbon black pearls to controlled thermal treatments, we obtained Fe-based electrocatalysts combining high surface area (628 m2 g−1) and catalytic activity for O2 reduction at near-neutral pH. The electrocatalysts were integrated on carbon cloth and carbon paper to obtain gas diffusion electrodes whose architecture was optimized to maximize MFC performance. Excellent cell performance was achieved with the carbon-paper-based cathode modified with the Fe-based electrocatalysts (maximum power density-PDmax = 1028 mWm−2) compared to a traditional electrode design based on carbon cloth (619 mWm−2), indicating the optimized cathodes as promising electrodes for energy recovery in an MFC application. [ABSTRACT FROM AUTHOR]

Transition metal oxides (TMOs) have great potential application in oxygen evolution reaction (OER). However, the inferior electrical conductivity and limited active sites of TMOs lead to their sluggish electrocatalytic efficiency. Herein, we adopted a two-step solvothermal approach to fabricate hierarchical CoO@NiO porous core–shell nanoarrays on carbon paper (denoted as CoO@NiO/CP). We found that numerous NiO nanofibers were uniformly coated over the surface of CoO nanosheets, forming a well-defined integrated interfacial nanocomposite. When acting as a catalyst for the OER, CoO@NiO/CP showed enhanced electroactivity with lower overpotential (323 mV at 10 mA cm−2), outstripping both pure CoO nanosheet array and NiO nanofiber array. Furthermore, it displayed outstanding OER stability, and the potential attenuation was only 3.4% after a 24 h chronopotentiometry test. The remarkable OER properties of CoO@NiO/CP were mainly due to its unique heterointerface between CoO and NiO, which promoted electron/charge transfer, increased electrocatalytic reactive sites, and improved electrical conductivity. Our presented findings provide a rational and practical interface-engineering approach for fabricating an advanced OER electrocatalyst. [ABSTRACT FROM AUTHOR]

Platinum-based catalysts exhibit outstanding electrocatalytic performance in the hydrogen evolution reaction (HER). However, platinum-based catalysts face significant challenges due to their rarity and high cost. This paper endeavors to shed light on a promising alternative: polyoxometalate (POM)-based catalysts, which possess significant potential for the synthesis of non-noble metal-based catalysts for the HER. Utilizing POMs as raw materials to assemble POM-derived materials, including POM-derived crystalline materials, metal sulfides, phosphides, carbides, nitrides, and so on, has emerged as an effective approach for the synthesis of hydrogen evolution electrocatalysts. This approach offers advantages in both stability and electrocatalytic performance. This comprehensive review navigates through latest progress in the assembly strategy and HER performance of POM-based crystal materials, alongside discussion on transition metal compounds derived from POMs, such as carbides, phosphides, and sulfides. Besides, future developments in POM-derived electrocatalyst regulation of the electrochemical HER are prospected. [ABSTRACT FROM AUTHOR]

Highlights: A carbon free self supported Mott-Schottky heterostructure was constructed as an efficient cathode catalyst for lithium oxygen batteries, achieving homogeneous contact between the two materials for strong interfacial interactions. The heterostructure triggered interfacial perturbations and band structure changes, which accelerated oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) kinetics, resulting in an extremely long cycle life of 800 cycles and an extremely low overpotential of 0.73 V. Combined with advanced characterization techniques and density functional theory calculations, the underlying mechanism behind the boosted ORR/OER activities and the electrocatalytic mechanism were revealed. Lithium-oxygen batteries (LOBs) with high energy density are a promising advanced energy storage technology. However, the slow cathodic redox kinetics during cycling causes the discharge products to fail to decompose in time, resulting in large polarization and battery failure in a short time. Therefore, a self-supporting interconnected nanosheet array network NiCo2O4/MnO2 with a Mott–Schottky heterostructure on titanium paper (TP-NCO/MO) is ingeniously designed as an efficient cathode catalyst material for LOBs. This heterostructure can accelerate electron transfer and influence the charge transfer process during adsorption of intermediate by triggering the interface disturbance at the heterogeneous interface, thus accelerating oxygen reduction and oxygen evolution kinetics and regulating product decomposition, which is expected to solve the above problems. The meticulously designed unique structural advantages enable the TP-NCO/MO cathode catalyst to exhibit an astounding ultra-long cycle life of 800 cycles and an extraordinarily low overpotential of 0.73 V. This study utilizes a simple method to cleverly regulate the morphology of the discharge products by constructing a Mott–Schottky heterostructure, providing important reference for the design of efficient catalysts aimed at optimizing the adsorption of reaction intermediates. [ABSTRACT FROM AUTHOR]

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Hydrogen, highly valued for its pristine cleanliness and remarkable efficiency as an emerging energy source, is anticipated to ascend to a preeminent status within the forthcoming energy landscape. Electrocatalytic water splitting is considered a pivotal, eco-friendly, and sustainable strategy for hydrogen production. The substantial energy consumption stemming from oxygen evolution side reactions significantly impedes the commercial viability of water electrolysis. Consequently, the pursuit of a cost-effective and efficacious oxygen evolution reaction (OER) catalyst stands as an imperative strategy for realizing hydrogen production via water electrolysis. Layered metal oxides, owing to their robust anisotropic properties, versatile adjustability, and extensive surface area, have emerged as suitable candidates for OER catalysts. However, owing to the distinctive attributes of layered metal oxides, ongoing investigations into these materials are slightly fragmented, lacking universal consensus. This article comprehensively surveys the recent advancements in layered metal oxide-based OER catalysts, categorized into single metal oxides, alkali cobalt oxides, perovskites, and miscellaneous metal oxides. Initially, the main OER intermediate reaction steps of layered metal oxides are scrutinized. Subsequently, the design, mechanism, and application of several pivotal layered metal oxides in the OER are systematically delineated. Finally, a summary is provided, alongside the proposal of future research trajectories and challenges encountered by layered metal oxides, with the aspiration that this paper may serve as a valuable reference for scholars in the field. [ABSTRACT FROM AUTHOR]

The paper studies the way of fabricating hydrogen evolution reaction (HER) electrocatalysts via pyrolysis of chemically synthesized composites based on conductive polymers (polyaniline, polypyrrole) with Prussian blue inclusions. Depending on the type of polymer in the initial composite, products of Prussian blue pyrolysis may differ. The use of polyaniline results in ultrafine spherical Fe3N particles, whereas polypyrrole facilitates the formation of both spherical and cylindrical Fe3С particles. The particles are formed within carbon matrices the structure of which is characterized by a significant amount of defects because of their doping with nitrogen atoms. The composite containing Fe3C inclusions, which was obtained with the use of polypyrrole, has a high enough electrocatalytic activity in acidic electrolyte, with its hydrogen evolution current density being of 10 mA/cm2 at overpotential of ‒230 mV. [ABSTRACT FROM AUTHOR]

The two-dimensional electrochemical Y2C's low work function and strong charge transfer qualities limit its applicability in catalysis due to its poor catalytic activity. In this paper, based on density functional theory calculations, we use two techniques to increase the HER catalytic activity of the Y2C monolayer: substitution doping (XC) and adsorption doping (XT) of non-metal (X = N, P, O, S, and F). The results showed that the absolute values of hydrogen free energies (ΔGH*) of the substitutional dopants of PC, SC and adsorptive dopants of NT, OT, ST, and PT had increased catalytic activity compared with those of the pristine Y2C monolayer (−0.673 eV). It was highlighted that the adsorption doping of PT can further reduce the adsorption free energy of the pristine Y2C monolayer to −0.19 eV, which is close to the optimal zero value, and the binding energy of the hydrogen atoms on the Y2C surface significantly increased from −0.913 to −0.438 eV, which is more favorable for the desorption of hydrogen atoms. These results demonstrate that the doping of non-metals activates the adsorption of hydrogen atoms on monolayer Y2C and provides a feasible method for hydrogen generation. [ABSTRACT FROM AUTHOR]

Electrochemical oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) has received increasing attention as it is an eco-friendly strategy for synthesizing a key monomer for the production of bio-based plastics. Developing efficient, low-cost and stable electrocatalysts is crucial for this electrochemical reaction. In this work, we have reported a facile process for the synthesis of hybrid nanosheet-structured NiCo2O4 on carbon fiber paper (NiCo2O4-CFP) for the efficient electrochemical conversion of HMF into FDCA. As a non-noble binary metal-based catalyst, NiCo2O4-CFP featured a nanosheet network and 3D nanosheet flower-like microspheres, showing 94.3% selectivity and 89.6% faradaic efficiency (FE) for FDCA, which outperformed its single component metal oxides NiO-CFP and Co3O4-CFP. And it also exhibited relatively high stability by maintaining over 80% FE after four successive cycles. The proposed mechanism suggested that the synergistic effect of Ni and Co elements in NiCo2O4 could facilitate HMF oxidation. [ABSTRACT FROM AUTHOR]

Graphene materials, used as electrocatalyst support in green hydrogen production, contribute to increasing the efficiency and robustness of various systems. However, the preparation of a hybrid catalyst containing graphene materials from industrial wastes is still a challenge due to the heterogeneity of the waste. We report the synthesis of 3D electrodes using graphene oxides (GOs) from industrial waste (IW) prepared by immersion onto Toray carbon paper as a 3D support onto GO suspensions and electrodepositing NiFe layered double hydroxides (LDHs). Standard graphite was also used as the reference. The morphology of the two hybrid electrodes was determined by SEM, HRTEM, XPS. Although very similar in both, the sample containing graphene from IW (higher Csp3 hybridization in the graphene layer) has a NiFe phase with less crystallinity and larger presence of Fe2+ ions. These electrodes exhibited similar activity and stability as electrocatalysts of the oxygen evolution reaction (OER), demonstrating the proactive effect of the graphene into the 3D electrode even when this is prepared from heterogeneous industrial waste. Moreover, the defective graphenic structure of the waste GO enhances the reaction kinetics and improves the electron transfer rate, possibly due to the small differences in the electrodeposited NiFe LDH structure. [ABSTRACT FROM AUTHOR]

The electrocatalytic nitrogen reduction reaction (eNRR) under ambient conditions is deemed a promising alternative for NH3 synthesis. In this paper, an FeP–Fe3O4 nanocomposite electrocatalyst was prepared by phosphating annealing using Fe2O3 as a precursor, and the resulting FeP–Fe3O4 exhibited excellent N2-to-NH3-producing activity over a wide potential window. The highest faradaic efficiency of FeP–Fe3O4 is 11.02% at −0.1 V vs. reversible hydrogen electrode (RHE), and the maximum NH3 yield reaches 12.73 μg h−1 mgcat−1, comparable to or exceeding the reported values in this field. Furthermore, the FeP–Fe3O4 nanocomposite electrocatalyst presents high electrochemical stability, selectivity, and durability. [ABSTRACT FROM AUTHOR]

The discovery of a cutting-edged electrocatalyst for water-splitting is an immense challenge to developing metal–air batteries and fuel cells. Therefore, developing sophisticated electrocatalysts with high activity and stability based on non-noble metal elements remains a great challenge. Herein, we prepared efficient polyhedral Ni/Cu bimetallic MOFs that are synthesized by a simple solvothermal method, in which the incorporation of Ni enhances the electrocatalytic properties of CuBTC MOF with distinct molar ratios. Benefiting from the unique morphology, and the favourable effect of Ni incorporation, the polyhedral Ni/Cu bimetallic MOFs exhibit conspicuous efficiency towards OER. The optimized NiCuBTC (2 : 8) bimetallic MOF exhibited superior activity with an overpotential of 290 mV to reach the current density of 10 mA cm−2. Moreover, the NiCuBTC (2 : 8) MOF also shows better long-term stability. The present work shows a facile strategy to design and synthesize a NiCuBTC (2 : 8) MOF electrocatalyst, which offers superior electrocatalytic performance towards water electrocatalysis. [ABSTRACT FROM AUTHOR]

Cu-based catalysts have been promising materials for electrocatalytic reduction of carbon dioxide into C2+ products. However, the low selectivity of Cu-based catalysts for a single C2+ product limits their application. Herein, this work presents a strategy to modify the coordination environment of Cu-based MOF catalysts through the introduction of different doping atoms, aiming to improve the selectivity towards ethanol products. The CuIn-BTC-DBD catalyst exhibits an ethanol FE of 87% with a partial current density of −17 mA cm−2 at −1.4 V vs. RHE. Through experimental investigations, we reveal the modulation of the coordination environment of Cu-based MOFs through the doping of In atoms. This strategy improves the selectivity for ethanol products. This study provides a new approach to designing bimetallic Cu-based MOF electrocatalysts with high efficiency, mild conditions, and stable CO2RR to ethanol products. [ABSTRACT FROM AUTHOR]

The exploration of clean, environmentally friendly, efficient and economical metal electrocatalysts is becoming more and more in-depth, but catalyst activity and stability are still the main goals. Herein, a thin regular pentagonal rough nanosheet array (La-CoNiOOH@FeSe@NiSe/NF) grown on a three-dimensional porous conductive surface was designed and synthesized. The prepared electrode material exhibited good catalytic activity in 1 M KOH solution, required only 270 mV of overpotential to provide 10 mA cm−2 current density for the oxygen evolution reaction (OER), and showed excellent stability for at least 90 hours during the OER process. The characterization test results proved that the incorporation of La changed the surface electronic structure, optimized the interface, modulated the active site on the surface of the material, and exposed a large number of active sites, thus improving the activity and stability of the catalyst material. At the same time, such a rough surface also gives the material excellent wettability and anti-bubble adhesion, which is also a key factor in maintaining the catalytic activity and OER stability of the material. This method provides a new idea for developing an efficient and economical electrolytic hydroelectricity catalyst. [ABSTRACT FROM AUTHOR]

The development of highly efficient and bifunctional electrocatalysts for hydrogen evolution and glycerol oxidation in seawater electrolytes is of great significance for the production of high value-added chemicals. Herein, self-supported FeCoNiCuP high entropy alloy nanosheet arrays (HEANAs) were successfully synthesized on a carbon cloth substrate through a straightforward electrodeposition method. The resulting catalyst demonstrates remarkable performance towards glycerol oxidation reaction (GOR) with a low potential of 1.28 V at 10 mA cm−2 and an impressive formate Faradaic efficiency (FE) of 87.9%. Additionally, this catalyst exhibits excellent hydrogen evolution reaction (HER) performance. Theoretical calculations identify Fe and CuNiFe bridge sites of FeCoNiCuP as active centers for GOR and HER, respectively. Utilizing FeCoNiCuP HEANAs in the GOR-assisted electrolyzer achieves a substantially reduced potential of 1.40 V at 10 mA cm−2, producing formate at the anode and hydrogen at the cathode with high FE and outstanding stability. Furthermore, the catalyst maintains consistent performances in seawater electrolyte without interfering with chlorine evolution, offering a promising avenue for sustainable and environmentally friendly high-value chemical production. [ABSTRACT FROM AUTHOR]

Facile preparation of low-cost electrocatalysts for an efficient oxygen evolution reaction (OER) is significant but remains a big challenge. Herein, a novel and facile strategy for transforming intrinsic non-stoichiometric ultrathin Co5(O9.48H8.52)NO3 nanosheets into oxygen-vacancy enriched Co3O4/CoOOH heterostructure nanosheets for an efficient OER was developed. The as-synthesized Co3O4/CoOOH heterostructure nanosheets displayed excellent OER performances, showing an extremely low overpotential of 260 mV at a current density of 10 mA cm−2, a relatively small Tafel slope of 52 mV dec−1, and a long-term durability of at least 20 h. This work provides a new way for the production of oxygen vacancies on metal (oxy)hydroxide nanosheets through electric-field assisted in situ transformation of non-stoichiometric metal oxyhydroxide nanosheets. [ABSTRACT FROM AUTHOR]

The development of low-cost, efficient, and stable bifunctional electrocatalysts is very important for the development of renewable energy. Layered double hydroxides (LDHs) are considered to be promising electrocatalysts due to their flexible ion exchange, abundant structural adjustability, excellent thermal stability, and easy functionalization with other materials. In this work, nickel-cobalt layered double hydroxide (NiCo-LDH) nanosheet arrays are prepared by a simple hydrothermal method. Four samples Ni1Co4-LDH, Ni2Co3-LDH, Ni3Co2-LDH and Ni4Co1-LDH are obtained by adjusting the Ni/Co ratio (5 − x : x). Among them, the Ni2Co3-LDH samples show excellent HER and OER properties. At a current density of 50 mA cm−2 in a 1.0 M KOH electrolyte, the overpotentials of the HER and OER are 227 mV and 303 mV, respectively. In addition, as a bifunctional electrocatalyst for water splitting, the sample provides a voltage of 1.83 V and long-term stability at 50 mA cm−2. [ABSTRACT FROM AUTHOR]

Constructing highly efficient electrocatalysts is vital to enhance oxygen evolution reaction (OER) performance at industrially relevant current densities. Herein, three-phase coupled Ni3S2/r-NiS/h-NiS composites are grown in situ on Ni foam (NNSN/NF) via a one-step solvothermal approach. The as-prepared composites need overpotentials of only 377 mV, 451 mV and 476 mV at 1000 mA cm−2 for the OER in alkaline freshwater, simulated seawater and seawater, respectively. In addition, the optimized catalyst exhibited long-term durability at 300 mA cm−2. Our work clarifies designing and preparing cost-effective Ni-based sulfide electrocatalysts for the OER in alkaline freshwater/simulated seawater/seawater under industrially relevant current densities. [ABSTRACT FROM AUTHOR]

Pronounced compositional regulation and microstructure evolution have a significant influence on hydrogen electrocatalysis. Herein, for the first time, we demonstrate that N,Co-codoped carbon supported Co5.47N nanoparticles (Co5.47N/N,Co-C-800) derived from a nitrogen-rich porphyrin-bridged covalent triazine polymer (CoTAPPCC) are an effective electrocatalyst for the HER in 1.0 M KOH when compared to CoCo2O4/N,Co-C-900 (pyrolysis at 900 °C) and CoO/N,Co-C-1000 (pyrolysis at 1000 °C). The structural and morphological variations of CoTAPPCC at different heat treatment temperatures were investigated through various spectroscopic techniques. We reveal that electrocatalytic HER activity is temperature- and component-dependent. The overpotentials for Co5.47N/N,Co-C-800 to reach current densities of 10 and 100 mA cm-2 were determined to be 76 and 229 mV, respectively, outperforming many other state-of-the-art HER electrocatalysts. This work also sheds light on the influence of calcination temperature on the electrocatalytic HER of final samples. [ABSTRACT FROM AUTHOR]

Active and stable electrocatalysts based on earth-abundant elements for the acidic oxygen evolution reaction (OER) are crucial for hydrogen production using proton-exchange membrane water electrolyzers. Herein, nickel-doped manganese oxide nanorods (Ni–MnO2) are prepared using a hydrothermal method in an acidic environment. The nanorods exhibit moderate stability towards the OER in 0.1 M HClO4. Doping Ni enhances OER activity, which originates from the electronic interaction that tunes the adsorption energy of OH*, which is an important OER intermediate. The most active electrode exhibits an overpotential of 390 mV to reach 10 mA cm−2 OER current density in 0.1 M HClO4. All electrodes prepared are stable towards 10 mA cm−2 galvanostatic test for at least 5 h. The dissolution of Ni and Mn species is observed, and the crystalline phase transforms to the amorphous phase under prolonged OER. [ABSTRACT FROM AUTHOR]

A heterostructure based on MOFs with a small lattice mismatch is ideal for improving glucose's electrochemical sensing performance. Herein, a novel one‐pot carbothermal reduction technique to prepare Cu‐BTC@Cu/C heterostructure with intimate interfacial contact and high yield was developed, by in situ integrating Cu‐BTC (Cu3(BTC)2 ⋅ 3H2O) and its derived Cu/C nanocomposites. Structure characterizations demonstrated that Cu‐BTC@Cu/C heterostructure shows a synergistic effect in the combination of these two components, with more electrochemical active sites and lower resistance. Compared with each individual component, Cu‐BTC@Cu/C heterostructure exhibits better glucose electrooxidation performance. Under optimal condition, an extremely sensitive nonenzymatic glucose sensor with a low detection limit of 6.78 μM, sensitivity of 911.03 μA mM−1 cm−2, linear range of 0.001–2.0 mM, and anti‐interference performance is presented. Meanwhile, the newly constructed sensor was effectively employed for detecting glucose in honey sample with perfect recoveries, showing its great potential toward glucose monitoring in real sample. In addition, it has been demonstrated Cu(II) can be induced into Cu(I) by glucose in solution, while Cu(I) could be electrochemically converted to Cu(II), therefore achieving a Cu(I)/Cu(II) redox cycle. It offers a promising strategy for synthesis of advanced electrocatalysts with high efficiency and promising applications in this paper. [ABSTRACT FROM AUTHOR]

The hydrogen evolution reaction (HER), as a pivotal half-reaction, significantly hinders the advancement of energy conversion efficiency. Metal electrodeposition on catalysts has been demonstrated to effectively enhance the HER reactivity. Here, Ni3S2–Fe–Ni with a multilayer structure was obtained by the electrodeposition of Ni3S2 with dopants Fe/Ni, in which a number of active sites were achieved and the intrinsic conductivity of the catalyst was well improved. Elemental analyses revealed the multilayer structure consisting of Ni3S2, NiS, and Fe. The Ni3S2–Fe–Ni catalyst exhibited impressive electrochemical performance due to optimization of its structure with the overpotentials of the HER and OER of only 83 and 190 mV. Notably, at a higher current density of 100 mA cm−2, the overpotentials for the HER and OER are only 339 and 365 mV. As a bifunctional electrocatalyst, its total splitting voltage was only 1.55 V. The catalysis performance remained nearly unchanged even after 48 h of stability testing. Finally, density functional theory (DFT) calculations revealed that the potential barriers in each reaction step of the OER are evenly distributed, and optimizing the Ni3S2 structure with iron and nickel atoms reduced the reaction energy barriers during the electrochemical process, improving the OER/HER performance. [ABSTRACT FROM AUTHOR]

Tuning the activity, selectivity, and stability of electrocatalysts for the electrochemical CO2 reduction reaction (eCO2RR) is of high interest. Among the multitude of possible eCO2RR products, formic acid/formate is not only of high industrial importance but even more importantly it can be obtained at nearly 100 % Faradaic efficiency if suitable catalysts are employed for the eCO2RR. Recently, two distinct strategies to modulate the eCO2RR over Bi‐based catalysts, namely phase modulation and functionalization with organic ligands, have come to the fore. This concept paper aims to string them together to accelerate their exploitation to design sophisticated electrocatalysts for the eCO2RR. [ABSTRACT FROM AUTHOR]

Transition metal–based catalysts are considered to be promising materials to replace noble metal catalysts for electrocatalytic water splitting. Herein, a flexible electrode composed of Co-Ni-P ternary catalysts and carbon fiber paper substrate (Co-Ni-P/CFP) was successfully fabricated and applied in water electrolysis. The Co-Ni-P coatings were deposited on CFP by a one-step cyclic voltammetric electrodeposition method and the surface of the composite material exhibits nano-reticular structure. The formation mechanism was also discussed according to the results of material characterization. Notably, the Co-Ni-P/CFP flexible electrode exhibited superior catalytic performance for both hydrogen and oxygen evolution reactions in alkaline media, which could achieve 10 mA/cm2 current density with overpotential of 89 mV for HER and 320 mV for OER. Moreover, the Co-Ni-P/CFP electrode could also be used as both anode and cathode electrode to drive overall water splitting and required only 1.64 V to achieve a current density of 10 mA/cm2, which was very close to that of the commercial combination of Pt/C and IrO2. This affordable and easily obtained electrode offers a new avenue to develop earth-abundant resource catalysts for water electrolysis system. [ABSTRACT FROM AUTHOR]

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BACKGROUND: Fabrication of cost‐effective and durable materials for efficient hydrogen production in splitting water (hydrogen evolution reaction) is of importance for the successful utilization of hydrogen‐based green energy technologies. Therefore, electrocatalytic materials have been designed with a simple approach using electrodeposition of gold nanoparticles (AuNPs) and thin film (AuTF) directly on reduced graphene oxide (rGO) paper. As‐prepared paper electrocatalysts (AuNPs/rGO and AuTF/rGO) were characterized by X‐ray photoelectron spectroscopy (XPS), X‐ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM). RESULTS: Free‐standing and flexible AuNPs/rGO and AuTF/rGO electrocatalysts have exhibited excellent performances on HER with low Tafel slopes (88 and 112 mV dec−1), low onset potentials (−47 and −55 mV), small overpotentials of only −176 and −204 mV to drive 10 mA cm−2, respectively, and high durability even with the rolled design. The outstanding performance of these two electrocatalysts can be attributed to the uniform distribution of 20‐nm‐sized AuNPs and the deposition of well‐ordered AuTF on rGO paper, providing an increment in the surface area and an enhancement of the electron density. CONCLUSION: The controllable design of AuNPs/rGO and AuTF/rGO electrocatalysts, together with their high flexibility, good stability and promising results, suggest potential use in future applications of H2 production in splitting water. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Fe/N-doped carbon (Fe-NC) is an excellent base-metal catalyst for use in an electrocatalytic oxygen reduction reaction (ORR) with high activity. In this paper, graphite phase carbon nitride (g-C3N4) was first obtained from the pyrolyzing of melamine, and then different proportions of FeCl3 were separately doped into g-C3N4 to further prepare the Fe-NC catalyst. The Fe-NC catalyst was applied in an ORR reaction, and the results show that the Fe-NC catalyst doped with 0.5 mmol FeCl3 possesses exceptional electrocatalytic performance, with an onset potential of 0.96 V and a half-wave potential of 0.81 V, which approaches that of a Pt/C catalyst. Meanwhile, the Fe-NC catalyst displays high stability and methanol resistance. The results supply a new way to prepare efficient ORR electrocatalysts. [ABSTRACT FROM AUTHOR]

[Objective] The problems of excessive CO2 emission, the greenhouse effect, and energy shortage have been widely discussed among countries worldwide. Electrocatalytic CO2 reduction reaction (ECO2RR) can realize the conversion of CO2 into value-added chemical fuel under mild conditions and the storage of renewable electricity, which is an effective way to promote China's aim of carbon peak and carbon neutrality. To pursue higher catalytic activity and product selectivity, researchers are committed to developing highly efficient ECO2RR electrocatalysts. In this paper, we designed Mo2CO2 MXene-based single-atom catalysts (SACs) (TM@Mo2CO2-Ov, TM = Fe, Co, Ni) according to the needs of ECO2RR, focusing on their electronic structure, catalytic performance, as well as reaction mechanism through theoretical simulation of the electrocatalytic process. [Methods] In this work, the CIF file of the Mo2CO2 MXene structure downloaded from the crystal structure database was first imported into the Materials Studio software. Then, the (110) crystal plane was cleaved, and a vacuum layer of 15 A was created. Afterward, a 3 x 3 supercell treatment was applied to the system. Next, the VASP software was utilized to perform structure optimization. After the Mo2CO2 structure was optimized, a vacancy site for an oxygen atom on the surface was constructed. Subsequently, the Fe, Co, and Ni metal atoms were introduced into the respective vacancy sites to create the Fe@Mo2CO2-Ov, Co@Mo2CO2-Ov, and Ni@Mo2CO2-Ov catalyst models, respectively. Finally, the VASP software was employed to optimize the catalyst structures and the adsorption structures of the reaction intermediates. The performance evaluation of ECO2RR on different SACs was obtained by studying the reaction mechanism of the production of C products (CO, HCOOH, CH3OH, and CH4). The free energy of ECO2RR was calculated using the computational hydrogen electrode mode, wherein the energy of (H+ + e-) remained equivalent to that of 1/2H2 at normal pressure and temperature. [Results] The calculated results showed the following: 1) In the Mo2CO2-Ov framework, single Fe, Co, and Ni atoms replaced the Mo atom at the center of the O defect. After structural optimization, it was found that these three structures did not change significantly, and the bond lengths only changed slightly. 2) The CO2 molecule was stably adsorbed on Fe@Mo2CO2-Ov, Co@Mo2CO2-Ov, and Ni@Mo2CO2-Ov via chemisorption. The structures of CO2 were significantly bent after adsorption, and the calculated absolute values of the interaction exceeded four. The DOS analysis showed that the occupation of d orbitals of Ni, Co, and Fe led to the adsorption difference. The d orbitals of Co and Fe were hybridized with the ng and nM* orbitals of CO2, which promoted the adsorption and activation of CO2. 3) The ECO2RR free energy diagram and reaction path analysis showed that Co@Mo2CO2-Ov had higher ECO2RR activity and better CH4 selectivity and was a better electrocatalyst for the formation of C1 products from ECO2RR than Fe@Mo2CO2-Ov and Ni@Mo2CO2-Ov. [Conclusions] By integrating the geometrical analysis, DOS calculation, and free energy analysis, Co@Mo2CO2-Ov was established as the ideal ECO2RR catalyst. The work can achieve the expected goal of significantly enhancing the ECO2RR performance and improving students' scientific research literacy to explore micromechanisms and processes through the extension of the experimental process. [ABSTRACT FROM AUTHOR]

Reducing the use of fossil fuels is critical to human society. In recent years, electrocatalytic carbon dioxide (CO2) reduction has attracted widespread attention. A suitable CO2 reduction catalyst is essential to convert CO2 into more valuable chemical products with high selectivity and efficiency. In this paper, a highly selective ZnAlCe-Ternary metal hydroxides (ZnAlCe-THs) nanocomposite electrocatalyst material was designed and prepared, and its performance as an electrocatalyst for catalytic reduction of CO2 to carbon monoxide (CO) was explored. The layered structure of ZnAlCe-THs nanocomposites facilitates electron transfer as well as CO2 and proton transfer, providing a high specific surface area for the electroactive sites of the electrocatalytic reduction reaction. At the same time, the ZnAlCe-THs catalyst generates CO at an overpotential of − 0.5 V. At − 1.2 V versus the reversible hydrogen electrode (vs. RHE), the bias current density is about 10.46 mA cm−2 with high selectivity of 89.3% Faraday efficiency. Its excellent electrochemical properties make it a good catalyst for the selective reduction of CO2 to CO. In this paper, ZnAlCe-Ternary mental hydroxides (ZnAlCe-THs) with a layered hydrotalclike structure were prepared by hydrothermal and co-precipitation methods. It showed excellent catalytic performance in the electrocatalytic reduction of carbon dioxide to carbon monoxide with a Faraday efficiency of 89.3% at − 1.2 V vs. RHE and a current density of 10.46 mA cm−2 for higher selectivity for CO. In addition, the ZnAlCe-THs catalyst is stable and it can operate for 5 h without particularly significant deactivation. [ABSTRACT FROM AUTHOR]

It is a great challenge to synthesize efficient electrocatalysts for overall water splitting, especially non‐noble metal catalysts. Herein, one‐dimensional polycrystalline nanoneedles composed of CoO−Co9S8 nano heterostructures, in situ grown on carbon fiber paper are prepared for efficient overall water electrolysis. Due to strong electronic coupling, charge densities of Co2+/Co3+ in Co9S8 and Co2+ in CoO are favorably modified at the interface of CoO and Co9S8, resulting in optimized reaction intermediates absorption and greatly enhanced bifunctional HER/OER activities. CoO−Co9S8/CFP delivers a current density of 10 mA cm−2 in alkaline electrolyte at overpotentials of 184 mV and 270 mV for HER and OER, respectively. When used as electrocatalyst for overall water splitting, it needs a low cell potential of 1.66 V to realize water electrolysis at 10 mA cm−2. This work provides a new strategy to tune the electronic structures of transitional metal active sites via constructing nano heterostructures for efficient water electrolysis. [ABSTRACT FROM AUTHOR]

The development of heteroatom dual-doped porous carbon frameworks with uniform doping is highly desirable for achieving highly efficient oxygen reduction reaction (ORR) activity, due to their tunable chemical and electronic structures. Herein, porous covalent triazine-based frameworks (CTFs) incorporating nitrogen/chorine dual-doped porous carbon networks were fabricated by selecting 1,3-bis(4-cyanophenyl) imidazolium chloride as a building block, in a facile and controllable way via a bottom-up strategy. The resulting nitrogen/chorine dual-doped catalyst CCTF-700 exhibits excellent ORR performance with a more positive onset and half-wave potential (0.85 V vs. RHE), higher diffusion-limited current density and significantly improved stability in comparison with the benchmark commercial 20 wt% Pt/C catalyst. It is worth mentioning that CCTF-700 shows one of the best ORR performances among all the reported metal-free electrocatalysts under alkaline conditions. This work paves the way for a controllable and reliable strategy to craft highly efficient heteroatom dual-doped carbon catalysts for energy conversion. [ABSTRACT FROM AUTHOR]

The strategies for optimizing the morphology/structure and regulating the active sites of materials are effective ways to improve their electrocatalytic performance in the hydrogen evolution reaction (HER) and electrooxidation reaction. Herein, we demonstrate a facile strategy for constructing a NiO/NiCo2O4 porous nanowire catalyst on nickel foam (NiO/NiCo2O4/NF) as a bifunctional electrocatalyst to enhance the electrocatalytic performance for coupling the HER with the glucose oxidation reaction (GOR). Benefiting from the unique 1D porous nanowire structure and enhanced interfacial synergistic effect of the bicomponent catalyst, optimized NiO/NiCo2O4/NF-300 exhibited remarkable electrocatalytic activities for the GOR and HER with low potentials of 1.128 V and 0.212 V, respectively, at 100 mA cm−2. Moreover, the GOR exhibited a high yield of 72% for formic acid. This study provides a promising and simple strategy for the construction of 1D NiO/NiCo2O4 porous nanowire electrocatalysts with rich heterogeneous interfaces and paves a facile pathway for accelerating biomass electrochemical reaction-assisted hydrogen production. [ABSTRACT FROM AUTHOR]

Two new heteroleptic cobalt(III)dialkyldithiophosphate complex cations with a 1,2-bis(diphenylphosphino)ethane (dppe) ancillary ligand having formula [Co{S2P(OR)2}2(dppe)](B(C6H5)4) (R = –C2H5 (Co–Et); –CH(CH3)2 (Co–Pr)) have been synthesized and characterized spectroscopically as well as via single crystal X-ray diffraction analysis. The single crystal X-ray diffraction analyses reveal that the immediate geometries around Co(III) in both complexes are distorted octahedral, which are satisfied by four sulfur atoms of two dialkyldithiophosphate ligands and two phosphorus centers of the dppe ligand. These complex cations are neutralized by tetraphenyl borate B(C6H5)4 anions. The solid-state framework of both complexes are stabilized by C–H⋯π and C–H⋯C interactions. The nature of these interactions have been addressed with the help of Hirshfeld surface analysis, and percent contributions of pertinent interactions in the crystal structure of these complexes have been addressed using fingerprint plots. Both complexes have been used as heterogeneous electrocatalysts for the oxygen evolution reaction (OER). Results suggest that Co–Et is a better electrocatalyst for the OER, displaying an onset potential of 1.68 V and Tafel slope of 114 mV dec−1. Furthermore, in the homogeneous electrocatalysis of the hydrogen evolution reaction (HER) using trifluoroacetic acid, the overpotential for Co–Et and Co–Pr have been 1.05 V and 0.92 V, respectively, with turnover frequencies of 1518 s−1 and 287.5 s−1, respectively. Overall, heterogeneous OER and homogenous HER results suggest that Co–Et can be used as an efficient molecular electrocatalyst for oxygen/hydrogen evolution reactions. [ABSTRACT FROM AUTHOR]

Recent studies have shown that the networking and interaction between N, S, and CQDs activate reactions by creating additional active sites that bind more oxygen molecules. In this study, we used nitrogen-doped graphene quantum dots as a support for Ni–Au nanoparticles and investigated the influence of different Ni–Au ratios on the N-doped graphene quantum dots as an electrocatalyst for ethanol and formate oxidation. Indeed, three electrocatalysts containing gold and nickel nanoparticles are synthesized in 1 : 1, 1 : 3, and 3 : 1 (Ni1Au1, Ni1Au3, and Ni3Au1) ratios on the nitrogen-doped graphene quantum dots as a catalyst support by the reduction process. The synthesized electrocatalysts are characterized by XRD, FESEM, and EDX methods. The electrocatalytic activity of the Ni1Au1-NGQD, Ni1Au3-NGQD, and Ni3Au1-NGQD (nickel–gold–nitrogen-doped graphene quantum dot) electrocatalysts towards ethanol and formate oxidation are evaluated in half-cell and single-fuel cell configurations. The half-cell results confirm the superiority of the Ni1Au1-NGQD electrocatalyst towards oxidation of both fuels compared to the two other electrocatalysts, and the corresponding chronoamperometry shows its high stability. Therefore, the Ni1Au1-NGQD is used as an anodic electrocatalyst in a single fuel cell configuration using ethanol and formate as fuels and hydrogen peroxide as an oxidant. The maximum power density of 8.20 and 14.23 mW cm−2 is obtained at 60 °C with 2 M ethanol and 4 M formate as the fuel in a direct ethanol–hydrogen peroxide fuel cell (DEHPFC) and direct formate–hydrogen peroxide fuel cell (DFHPFC), respectively. [ABSTRACT FROM AUTHOR]

The development of excellent bifunctional electrocatalysts is an effective way to promote the industrial application of electrolytic water. In this work, a free-standing W-doped cobalt selenide (W-CoSe300/NF) electrocatalyst with a snowflake-like structure supported on nickel foam was prepared by a hydrothermal–selenization strategy. Benefiting from the high specific surface area of the 3D snowflake-like structure and the regulation of tungsten doping on the electronic structure of the metal active center, W-CoSe300/NF shows remarkable electrocatalytic water decomposition performance. In 1.0 M KOH, the W-CoSe300/NF electrocatalyst achieved an efficient HER and OER at a current density of 50 mA cm−2 with overpotentials as low as 84 mV and 283 mV, respectively. More importantly, W-CoSe300/NF acts as both the anode and cathode of the electrolytic tank, requiring only a potential of 1.54 V to obtain 10 mA cm−2 and can operate continuously for more than 120 hours at this current density. This study proposes a new way for the design of high efficiency and affordable bifunctional electrocatalysts. [ABSTRACT FROM AUTHOR]

In this report, we elucidated the hydrogen evolution reaction (HER) catalytic activity of different metal-azaphthalocyanine unimolecular layer (AZUL) catalysts and compared the overpotentials in alkaline electrolyte membrane water electrolysis (AEMWE). While the overpotentials are bit higher compared to Pt/C, the system utilizing the FeAzPc-4N with Sustainion® showed a low overpotential of 2.02 V at 1.0 A/cm2 and faraday efficiency of 96.3% even among the previous alternative catalysts. It is noteworthy that the AZUL catalysts are not using precious metals and even comparing with other transition metal electrocatalysts, metal atom usage is much lower because only the single transition metal atom in the azapthalocyanine macrocycle works as a catalytic site. [ABSTRACT FROM AUTHOR]

The unsatisfactory performance of the oxygen evolution reaction (OER) and the complex preparation methods are the main challenges hindering the industrial application of OER electrocatalysts in electrochemical water splitting for hydrogen production. Herein, a convenient two-step method including electrodeposition and subsequent chemical bath deposition was utilized to synthesize a FeOOH/Ni/NiO tri-component composite on Ti mesh (TM), during which Ni(Ac)2 and FeSO4 were used as feedstocks. XRD, Raman, XPS, SEM and TEM characterizations revealed nanosheet-assembled nanospheres composed of crystalline Ni coated by amorphous NiO, and amorphous FeOOH nanosheets successively deposited on the TM surface by electrodeposition and chemical bath deposition strategies. When serving as the OER electrocatalyst, the optimized FeOOH/Ni/NiO/TM presented a superb OER performance with an overpotential of 246 mV at 50 mA cm−2, outperforming FeOOH-5/NF (321 mV), Ni/NiO/TM (348 mV) and the recently reported electrocatalysts. Additionally, its OER performance had no obvious change with only 4.3% attenuation after working for 16 h at a constant current density. The high OER performance could be assigned to the interfacial electronic engineering due to the strong coupling effect between FeOOH and Ni/NO, which increased the intrinsic activity of the active sites, modulated the adsorption of the reactant and also enhanced the stability. The simple preparation strategy, low cost and high performance endow the self-supporting FeOOH/Ni/NiO/TM with potential applications in industrial water electrolysis for hydrogen production. [ABSTRACT FROM AUTHOR]

To develop hydrogen energy production and address the issues of global warming, inexpensive, effective, and long-lasting transition metal-based electrocatalysts for the synthesis of hydrogen are crucial. Herein, a porous electrocatalyst NiMo/Ni/NF was successfully constructed by a two-step electrodeposition process, and was used in the hydrogen evolution reaction (HER) of electrocatalytic water decomposition. NiMo nanoparticles were coated on porous Ni/NF grown on nickel foam (NF), leading to a resilient porous structure with enhanced conductivity for efficient charge transfer, as well as distinctive threedimensional channels for quick electrolyte diffusion and gas release. Notably, the low overpotential (42 mV) and fast kinetics (Tafel slope of 44 mV dec-1) at a current density of 10 mA cm-2 in 1.0 M KOH solution demonstrate the excellent HER activity of the electrode, which was superior to that of recently reported non-noble metal-based catalysts. Additionally, NiMo/Ni/NF showed extraordinary catalytic durability in stability tests at a current density of 10 mA cm-2 for 70 h. The porous structure catalyst and the electrodeposition-electrocatalysis technique examined in this study offer new approaches for the advancement of the electrocatalysis field because of these benefits. [ABSTRACT FROM AUTHOR]

Transition metal phosphides (TMPs) have attracted extensive interest to catalyze the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). However, the development of TMPs with high conductivity is a great challenge. Herein, we report hybrids of cobalt phosphide (CoP) and copper phosphide (CuP) strongly coupled with ZIF-67 derived carbon as bifunctional ORR/OER electrocatalysts (CoP/CuP@NC). The as-prepared CoP/CuP@NC catalysts exhibit delightful activity and stability toward the ORR (E1/2 = 0.86 V) and the OER (E10 = 1.61 V). Moreover, the assembled Zn-air battery exhibits a small charge-discharge voltage gap and excellent stability. These remarkable electrocatalytic capabilities stem from the combined impact of active CoP/CuP components and the structural framework derived from ZIF-derived materials. This work provides a meaningful strategy for constructing high-performance bifunctional electrocatalysts for commercial Zn-air batteries. [ABSTRACT FROM AUTHOR]

The large-scale use of zinc–air batteries (ZABs) has been limited by their sluggish OER and ORR kinetics. The current synthesis of catalysts for air electrodes requires harsh conditions. The design and manufacture of bifunctional catalysts under mild conditions are of great significance. Herein, an electric field-induced phosphorization at room temperature is proposed to prepare bifunctional electrocatalysts designed by coupling N-doped carbon and CoP nanoparticles based on a multi-active site-integration strategy. The simple, safe, non-toxic and highly controllable electric field-induced reaction creates CoP active sites. The catalyst exhibits a remarkably narrow potential gap (ΔE) of 0.65 V between the half-wave potential of the ORR and the potential of the OER. The low ΔE signifies a superior catalytic bifunctionality of CoP@NWC. Aqueous ZABs with an optimized catalyst achieve a high discharge specific capacity of 805.8 mA h gZn−1 and long-term cycling stability over 1200 cycles. Quasi-solid-state ZABs show a discharge-specific capacity of 760.5 mA h gZn−1. The outstanding bifunctional catalytic activities originate from the synergistic effect of dual active sites between CoP and NWC induced by the electric field. This work provides a new perspective for building advanced catalysts from biomass under ambient conditions. [ABSTRACT FROM AUTHOR]