Electrodeposited Nickel-Cobalt-Sulfide Catalyst for the Hydrogen Evolution Reaction

Construction of thickness-controllable bimetallic sulfides/reduced graphene oxide as a binder-free positive electrode for hybrid supercapacitors

Devices for electrochemical energy storage with exceptional capacitance and rate performance, outstanding energy density, simple fabrication, long-term stability, and remarkable reversibility have always been in high demand. Herein, a high-performance binder-free electrode (3D NiCuS/rGO) was fabricated as a supercapacitor by a simple electrodeposition process on a Ni foam (NF) surface. The thickness of the deposited materials on the NF surface was adjusted by applying a low cycle number of cyclic voltammetry (5 cycles) which produced a thin layer and thus enabled the easier penetration of electrolytes to promote electron and charge transfer. The NiCuS was anchored by graphene layers producing nicely integrated materials leading to a higher electroconductivity and a larger surface area electrode. The as-fabricated electrode displayed a high specific capacitance (2211.029 F g-1 at 5 mV s-1). The NiCuS/rGO/NF//active carbon device can achieve a stable voltage window of 1.5 V with a highly specific capacitance of 84.3 F g-1 at a current density of 1 A g-1. At a power density of 749 W kg-1, a satisfactory energy density of 26.3 W h kg-1 was achieved, with outstanding coulombic efficiency of 100% and an admirable life span of 96.2% after 10 000 GCD cycles suggesting the significant potential of the as-prepared materials for practical supercapacitors.

Highly Active NiO-Ni(OH)2 -Cr2 O3 /Ni Hydrogen Evolution Electrocatalyst through Synergistic Reaction Kinetics

High activity catalysts for hydrogen evolution reaction (HER) play a key role in converting renewable electricity to storable hydrogen fuel. Great effort has been devoted to the search for noble metal free catalysts to make electrolysis viable for practical applications. Here, a non-precious metal oxide/metal catalyst with high intrinsic activity comparable to Pt/C was reported. The electrocatalyst consisting of NiO, Ni(OH)2 , Cr2 O3 , and Ni metal exhibits a low overpotential of 27, 103, and 153 mV at current densities of 10, 100, and 200 mA cm-2 , respectively, in a 1.0 m NaOH electrolyte. The activity is much higher than that of NiOx /Ni or Cr2 O3 alone, showing the synergistic effect of NiOx /Ni and Cr2 O3 on catalyzing HER. Density functional theory calculations shows that NiO and Cr2 O3 on Ni surface lower the disassociation energy barrier for breaking H-OH bond, while Ni(OH)2 and Cr2 O3 create preferred sites on Ni surface with near-zero H* adsorption free energy to promote H* to gaseous H2 evolution. These synergistic effects of multiple-oxides/metal composition enhance the disassociation of H-OH and the evolution of H* to gaseous H2 , thus achieving high activity and demonstrating a promising composition design for noble metal free catalyst.

One-Dimensional Selenidostannates Based on an Infrequent Tetrameric Cluster [Sn4Se12] Exhibiting Electro-Catalytic Properties

The discovery of low-cost and efficient electro-catalytic materials for hydrogen evolution reaction (HER) is very desirable in hydrogen energy technology. Here, a new type of one-dimensional (1-D) organic hybrid selenidostannate [Ni(en)₃]_n[Sn₂Se₅]_n (SnSe-1, en = ethylenediamine) with an in situ [Ni(en)₃]²⁺ complex was achieved by the solvothermal reaction of Sn, Se, and NiCl₂·6H₂O in a mixed solvent of en and triethanolamine at 160 °C for 10 days. The crystal structure of SnSe-1 contains a unique 1-D [Sn₂Se₅^2-]_n chain built up from the sharing-edge connection of a hitherto-unknown tetrameric [Sn₄Se₁₂] cluster, which is separated by discrete [Ni(en)₃]²⁺ complexes. SnSe-1 is first combined with Ni nanoparticles supported on conductive porous Ni foam (NF) to constitute a Ni/SnSe-1/NF electrode as the HER electro-catalyst, displaying superior electro-catalytic activity in near-neutral conditions.

Infrequent Cubane-Like Chromium Sulfide Cluster with σ-Donor Ligands with Efficient Electrocatalytic Property Toward Hydrogen Evolution Reaction

The exploitation of efficient and economical electrocatalysts for hydrogen evolution reaction (HER) is of exceeding interest in renewable clean-energy technologies. Herein, the facile solvothermal reaction of S and chromic acetate in ethylenediamine (en) achieved a novel organic hybrid chromium sulfide [Cr₄(μ₃-S)₄(en)₄(SH)₄]·0.25H₂O (1), which offers a new type of antiferromagnetic cubane-like chromium sulfide cluster with σ-donor en ligands. 1 was utilized in combination with Ni nanoparticles and porous Ni foam (NF) to fabricate a Ni/1/NF electrode as an efficient cathodic catalyst, indicating excellent electrocatalytic property toward HER.

Nickel sulfide and phosphide electrocatalysts for hydrogen evolution reaction: challenges and future perspectives

The search for environmentally friendly and sustainable energy sources has become necessary to alleviate the issues associated with the consumption of fossil fuel such as air pollution and global warming. Furthermore, this is significant considering the exhaustible resources and burgeoning energy demand globally. In this regard, hydrogen, a clean fuel with high energy density, is considered a reliable alternative energy source. The hydrogen evolution reaction (HER) is one of the most promising methods to produce green hydrogen from water on a large scale. However, the HER needs effective electrocatalysts to address the concerns of energy consumption; thus, finding active materials has recently been the main focus of researchers. Among the various electrocatalysts, nickel sulfides and phosphides and their derivatives with low cost, high abundance, and relatively straightforward preparation have shown high HER activity. In this review, we compare the diverse methods in the synthesis of nickel sulfides and phosphides together with effective synthesis parameters. Also, the optimum conditions for the preparation of the desired active materials and their properties are provided. Then, the performance of nickel sulfide and phosphide electrocatalysts in the HER is addressed. The HER activity of the various crystalline phases is compared, and their most active crystalline phases are introduced. Finally, the present challenges and perspectives for future HER electrocatalysts are presented.

Sodium Hexa-Titanate Nanowires Modified with Cobalt Hydroxide Quantum Dots as an Efficient and Cost-Effective Electrocatalyst for Hydrogen Evolution in Alkaline Media

A novel electrocatalyst with high activity and enhanced durability toward the hydrogen evolution reaction (HER) in alkaline media has been designed and fabricated based on sodium hexa-titanate (Na₂Ti₆O₁₃) nanowires synthesized by a hydrothermal process and modified with Co(OH)₂ quantum dots (QDs) by a facile chemical bath deposition (CBD) method. The current response of the developed Ti/Na₂Ti₆O₁₃/Co(OH)₂ nanocomposite electrode attained 10 mA cm^-2 at an overpotential of 159 mV. The nanocomposite electrode exhibited a high stability at an applied current of 100 mA cm^-2. The remarkable catalytic behavior was achieved with a loading amount of ca. 0.06 mg cm^-2 cobalt hydroxide. This is attributed to the high electrochemically active surface area (EASA) gained by the nanowire-structured substrate and considerable enhancement of electrochemical conductivity with the use of Co(OH)₂ quantum dots as an active material. The superior catalytic activity and high stability show that the developed catalyst is a promising candidate for hydrogen production in alkaline media.

Highly Efficient Water Splitting Catalyst Composed of N,P-Doped Porous Carbon Decorated with Surface P-Enriched Ni2P Nanoparticles

A non-noble-metal hybrid catalyst (Ni₂P/NPC-P), composed of N,P-doped porous carbon decorated with surface P-enriched Ni₂P nanoparticles, is developed to address the urgent challenges associated with mass production of clean hydrogen fuel. The synthesis features one-pot pyrolysis of inexpensive fluid catalytic cracking slurry, graphitic carbon nitride, and inorganic salts, followed by a feasible surface phosphidation process. As a non-noble metal catalyst, Ni₂P/NPC-P demonstrates excellent performance in hydrogen evolution reaction in alkaline electrolytes with a low overpotential of 73 mV at a current density of 10 mA cm^-2 (η₁₀) and a small Tafel slope of 56 mV dec^-1, meanwhile exhibits durability with no significant η₁₀ change after 2000 catalytic cycles. Theoretical calculation reveals that the negatively charged P-enriched surface accelerated the rate-determining transformation and desorption of OH*. In overall water splitting, the electrocatalyst achieves a low η₁₀ of 1.633 V, promising its potential in the cost-effective mass production of hydrogen fuel.

Modeling of the Simultaneous Hydrogen Evolution and Cobalt Electrodeposition

A mathematical model of simultaneous cobalt deposition and hydrogen evolution was developed and applied to the electroreduction process of 5 mM Co 2+ ions investigated by cyclic voltammetry (CV) technique at different hydrogen ion concentrations (pH = 2, 3, 4). The kinetic parameters of such a complex process were determined, and the validity of the model and its sensitivity to changes in individual parameters were verified. The relative value of the approximate standard deviation (ASD % ) was used to determine the degree of fit of the model to the experimental data. The catalytic effect of cobalt on the hydrogen evolution process was comprehensively confirmed.

All-Electrochemical Nanofabrication of Stacked Ternary Metal Sulfide/Graphene Electrodes for High-Performance Alkaline Batteries

Energy-storage materials can be assembled directly on the electrodes of a battery using electrochemical methods, this allowing sequential deposition, high structural control, and low cost. Here, a two-step approach combining electrophoretic deposition (EPD) and cathodic electrodeposition (CED) is demonstrated to fabricate multilayer hierarchical electrodes of reduced graphene oxide (rGO) and mixed transition metal sulfides (NiCoMnS_x ). The process is performed directly on conductive electrodes applying a small electric bias to electro-deposit rGO and NiCoMnS_x in alternated cycles, yielding an ideal porous network and a continuous path for transport of ions and electrons. A fully rechargeable alkaline battery (RAB) assembled with such electrodes gives maximum energy density of 97.2 Wh kg^-1 and maximum power density of 3.1 kW kg^-1 , calculated on the total mass of active materials, and outstanding cycling stability (retention 72% after 7000 charge/discharge cycles at 10 A g^-1 ). When the total electrode mass of the cell is considered, the authors achieve an unprecedented gravimetric energy density of 68.5 Wh kg^-1 , sevenfold higher than that of typical commercial supercapacitors, higher than that of Ni/Cd or lead-acid Batteries and similar to Ni-MH Batteries. The approach can be used to assemble multilayer composite structures on arbitrary electrode shapes.

Ruthenium-Doping-Induced Amorphization of VS4 Nanostructures with a Rich Sulfur Vacancy for Enhanced Hydrogen Evolution Reaction in a Neutral Electrolyte Medium

The generation of pure H₂ from a neutral electrolyte solution represents a transformative route with low cost and environmentally friendly nature. However, the complex kinetics of hydrogen evolution reaction (HER) via water electrolysis make its practical application to be difficult. Herein, we have reported Ru-doping-induced formation of VS₄ nanostructures with a rich S vacancy for neutral HER in a 0.2 M phosphate buffer solution. The Ru-doped VS₄ demands an overpotential value of 160 mV at 10 mA/cm² current density with a lower catalyst loading of 0.1 mg/cm², while pristine VS₄ demands a 374 mV overpotential with the same mass loading. 60 hours of chronoamperometric study reveals the excellent stability of Ru-doped VS₄ materials, which is the highest amount of time ever reported for neutral HER. The marginal degradation of a catalyst under a long-term stability study was confirmed through inductively coupled plasma mass spectrometry (ICP-MS) analysis. The introduction of Ru to the VS₄ lattice leads to a 4.35-fold increase in the turnover-frequency values compared to those of bare VS₄ nanostructures. The higher HER activity of S-vacancy-enriched VS₄ materials is thought to originate through effective water adsorption in S vacancy and Ru³⁺ sites followed by the dissociation of a H₂O molecule, and S₂^2- efficiently converts H_ad to H₂. Also, post-HER characterization reveals that the transformation of some Ru³⁺ to Ru⁰ additionally favored the HER by providing a better H adsorption site under a static cathodic potential.

Electronic wastes: A near inexhaustible and an unimaginably wealthy resource for water splitting electrocatalysts

E-wastes comprise complex combinations of potentially toxic elements that cause detrimental effects of the environmental contamination; besides their posing threat, most of the products also contain valuable and recoverable materials (Li, Au, Ag, W, Se, Te, etc.), which make them distinct from other forms of industrial wastes. Most of these value-added elements which are primarily employed in electronic goods are disposed of by incineration and land-filling. This is a serious issue besides just environmental pollution, as IUPAC recognized that such ignorance of or poor attention to e-waste recycling has put several elements in the periodic table to the list of endangered elements. Recycling these wastes utilized for electrocatalytic water splitting to produce H₂. These recovered e-wastes materials are used as electrocatalysts for the water-splitting, additives to enhance reaction kinetics, and substrate electrodes as well. Recycling and recovery of value-added materials in the view of applying them to electrocatalytic water splitting with endangered elements' perspective have not been covered by any recent review so far. Hence, this review is dedicated to discussing the opportunities available with recycling e-wastes, types of value-added materials that can be recovered for water splitting, strategies exploited, and prospects are discussed in details.

Electrochemically Deposited Amorphous Cobalt-Nickel-Doped Copper Oxide as an Efficient Electrocatalyst toward Water Oxidation Reaction

Production of hydrogen through water splitting is one of the green and the most practical solutions to cope with the energy crisis and greenhouse effect. However, oxygen evolution reaction (OER) being a sluggish step, the use of precious metal-based catalysts is the main impediment toward the viability of water splitting. In this work, amorphous copper oxide and doped binary- and ternary-metal oxides (containing CoII, NiII, and CuII) have been prepared on the surface of fluorine-doped tin oxide by a facile electrodeposition route followed by thermal treatment. The fabricated electrodes have been employed as efficient binder-free OER electrocatalysts possessing a high electrochemical surface area due to their amorphous nature. The cobalt-nickel-doped copper oxide (ternary-metal oxide)-based electrode showed promising OER activity with a high current density of 100 mA cm-2 at 1.65 V versus RHE that escalates to 313 mA cm-2 at 1.76 V in alkaline media at pH 14. The high activity of the ternary-metal oxide-based electrode was further supported by a smaller semicircle in the Nyquist plot. Furthermore, all metal-oxide-based electrodes offered high stability when tested for continuous production of oxygen for 50 h. This work highlights the synthesis of efficient and cost-effective amorphous metal-based oxide catalysts to execute electrocatalytic OER employing an electrodeposition approach.

Sulfurization-induced partially amorphous palladium sulfide nanosheets for highly efficient electrochemical hydrogen evolution

Partially amorphous PdS was synthesized by sulfurizing crystalline palladium nanosheets via a facile method, displaying excellent activity and stability towards hydrogen evolution in alkaline media.

Morphological and reactive optimization of g-C3N4-derived Co,N-codoped carbon nanotubes for hydrogen evolution reaction

Scheme for the synthesis of bamboo-like N-doped carbon nanotubes.

CoP and Ni2P implanted in a hollow porous N-doped carbon polyhedron for pH universal hydrogen evolution reaction and alkaline overall water splitting

Developing low-cost and highly active bifunctional electrocatalysts for water splitting is very important but still remains a challenge. Herein, a novel bifunctional electrocatalyst composed of CoP and Ni2P nanoparticles implanted in a hollow porous N-doped carbon polyhedron (CoP/Ni2P@HPNCP) is synthesized by carbonization of Co/Ni-layered double hydroxide@zeolitic imidazolate framework-67 (Co/Ni-LDH@ZIF-67) followed by an oxidation and phosphorization strategy. The introduction of LDH can not only promote the formation of a hollow porous structure to supply more active sites, but also generate the CoP/Ni2P nanoheterostructure to afford extra active sites and modulate the electronic structure of the catalyst. As a result, CoP/Ni2P@HPNCP exhibits excellent pH universal hydrogen evolution reaction activity and alkaline oxygen evolution reaction activity. Furthermore, the electrolytic cell assembled from bifunctional CoP/Ni2P@HPNCP requires a cell voltage of 1.59 V in 1.0 M KOH at 10 mA cm-2, revealing its potential as a high performance bifunctional electrocatalyst.

Mesoporous Nanostructured Composite Derived from Thermal Treatment CoFe Prussian Blue Analogue Cages and Electrodeposited NiCo-S as an Efficient Electrocatalyst for an Oxygen Evolution Reaction

Developing effective and priceless electrocatalysts is an indispensable requirement for advancing the efficiency of water splitting to get clean and sustainable fuels. Herein, we reported a feasible strategy for preparing a trimetallic (NiCoFe) superior electrocatalyst with a novel open-cage/3D frame-like structure for an oxygen evolution reaction (OER). It is prepared by consequent thermal treatments of a CoFe Prussian blue analogue frame/cage-like structure under an argon (CoFeA-TT) atmosphere and then electrochemical deposition of nickel-cobalt sulfide nanosheets as a shell layer on it. The electrochemical measurements demonstrated that the deposition of NiCo-S on CoFeA-TT (NiCo-S@CoFeA-TT) has the best catalytic performance and can drive the benchmark current density of 10 mA cm^-2 at a low overpotential of 268 mV with a Tafel slope of 62 mV dec^-1 and an excellent long-term catalytic stability in an alkaline medium. Its outstanding electrocatalytic performances are endowed from frame/cage-like structures, highly exposed active sites, accelerated mass and electron transport, and the synergistic effect of multiple hybrid components. The NiCo-S@CoFeA-TT showed a better performance than most advanced nonprecious catalysts and the noble commercial RuO₂ catalyst. This study exhibited an effective and efficient procedure to design 3D porous architecture catalysts for the energy-relevant electrocatalysis reaction.

Efficient All-2D Amorphous Cobalt Sulfide Nanosheets/Multilayered Molybdenum Disulfide Hybrid Heterojunction Catalyst for Electrochemical Hydrogen Evolution

Hydrogen energy is considered to be a critical environmentally friendly and widely sourced renewable energy source that can be used as an alternative to fossil fuels. At present, the preparation of hydrogen (H2) mainly depends on traditional fossil fuels. In order to achieve sustainable development of environmental protection, great attention has been paid to the preparation of H2 by electrocatalysis, photocatalysis, and photoelectrochemistry. Here, it is reported for the first time that a novel active catalyst for the hydrogen evolution reaction, consisting of all-2D amorphous nanosheets/2D crystal layer heterojunction structure and without any noble metal (no precious metals are present in the preparation or measuring), is almost entirely fabricated by laser ablation in liquid (LAL) growth of amorphous cobalt sulfide on the surface of multilayered molybdenum disulfide. In acidic media, the amorphous cobalt sulfide nanosheets/multilayered molybdenum disulfide (a-CoS/MoS2) catalyst exhibits fast hydrogen evolution kinetics with onset potential of -147 mV and a Tafel slope of 126 mV per decade, which is much better than only the amorphous cobalt sulfide and molybdenum disulfide layer. The high hydrogen evolution activity of the amorphous cobalt sulfide nanosheets/multilayered molybdenum disulfide hybrid is likely due to the unique electrocatalytic synergistic effects between hydrogen evolution-active amorphous cobalt sulfide nanosheets and layered crystal molybdenum disulfide materials, as well as the much-increased catalytic sites. This work provides a new general route based on all-2D amorphous nanosheets/2D crystal structure for designing and preparing novel layered materials with effectively manipulated catalytic properties and active functionality surface.

5.1% efficiency of Si photoanodes for photoelectrochemical water splitting catalyzed by porous NiFe (oxy)hydroxide converted from NiFe oxysulfide

A porous NiFe (oxy)hydroxide catalyst fabricated on n+pp+-Si/Ni/NiOx, which is converted from an electrodeposited NiFe oxysulfide, allows a silicon photoanode for water splitting to hit a record 5.1% efficiency with good stability of up to 135 h under 40 mA cm-2 in 1.0 M NaOH.

Electrodeposition of Ni-Co-Fe mixed sulfide ultrathin nanosheets on Ni nanocones: a low-cost, durable and high performance catalyst for electrochemical water splitting

The development of a bi-functional active and stable catalyst for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is an important challenge in overall electrochemical water splitting. In this study, firstly, nickel nanocones (NNCs) were formed using electrochemical deposition, and then Ni-Co-Fe based mixed sulfide ultrathin nanosheets were obtained by directly depositing on the surface of the nanocones using the CV method. With a hierarchical structure of Ni-Fe-Co-S nanosheets, not only was a high active surface area created, but also the electron transfer and mass transfer were enhanced. This structure also led to the faster release of hydrogen bubbles from the surface. An overpotential value of 106 mV was required on the surface of this electrode to generate a current density of 10 mA cm^-2 in the HER, whereas, for the OER, 207 mV overpotential was needed to generate a current density of 10 mA cm^-2. Furthermore, this electrode required 1.54 V potential to generate a current density of 10 mA cm^-2 in the total electrochemical water splitting. The resulting electrode also exhibited reasonable electrocatalytic stability, and after 10 hours of electrolysis in the overall water splitting reaction, the voltage change was negligible. This study introduces a simple, efficient, reasonable and cost-effective method of creating an effective catalyst for the overall water splitting process.

Engineering Ternary Copper-Cobalt Sulfide Nanosheets as High-performance Electrocatalysts toward Oxygen Evolution Reaction

The rational design and development of the low-cost and effective electrocatalysts toward oxygen evolution reaction (OER) are essential in the storage and conversion of clean and renewable energy sources. Herein, a ternary copper-cobalt sulfide nanosheets electrocatalysts (denoted as CuCoS/CC) for electrochemical water oxidation has been synthesized on carbon cloth (CC) via the sulfuration of CuCo-based precursors. The obtained CuCoS/CC reveals excellent electrocatalytic performance toward OER in 1.0 M KOH. It exhibits a particularly low overpotential of 276 mV at current density of 10 mA cm−2, and a small Tafel slope (58 mV decade−1), which is superior to the current commercialized noble-metal electrocatalysts, such as IrO2. Benefiting from the synergistic effect of Cu and Co atoms and sulfidation, electrons transport and ions diffusion are significantly enhanced with the increase of active sites, thus the kinetic process of OER reaction is boosted. Our studies will serve as guidelines in the innovative design of non-noble metal electrocatalysts and their application in electrochemical water splitting

Accelerating the water splitting kinetics of CoP microcubes anchored on a graphene electrocatalyst by Mn incorporation

CoP is considered as an efficient electrocatalyst for the hydrogen evolution reaction (HER) in acidic electrolytes but its performance in alkaline solutions is generally poor because of its slow reaction kinetics, which further limits its application in overall water splitting. Herein, we demonstrate a strategy to greatly accelerate its HER and OER kinetics in alkaline solutions through Mn incorporation. Ternary Mn x Co1-x P microcubes with a tunable Mn/Co ratio strongly anchored on rGO were synthesized using Prussian blue analogues as precursors. The synergy between the high activity of Mn x Co1-x P microcubes and the good conductivity of rGO leads to the superior performance of the hybrid toward water splitting in 1 M KOH. The optimized Mn0.6Co0.4P-rGO electrocatalyst shows high activity and stability towards both the HER and OER with low overpotentials of 54 and 250 mV at 10 mA cm-2, respectively. Furthermore, the water electrolyzer using Mn0.6Co0.4P-rGO as both the cathode and anode only requires a cell voltage as low as 1.55 V to reach a current density of 10 mA cm-2, making Mn0.6Co0.4P-rGO a competitive and cost-effective electrocatalyst for water splitting.

3D flower-like CoNi2S4/polyaniline with high performance for glycerol electrooxidation in an alkaline medium

Schematic of the fabrication of CoNi₂S₄/PANI.

Hierarchical whisker-on-sheet NiCoP with adjustable surface structure for efficient hydrogen evolution reaction

We have reported the synthesis of hierarchical whisker-on-sheet (HWS) NiCoP anchored on Ni foam with adjustable surface structure for efficient hydrogen evolution reaction (HER). The HWS NiCoP was obtained by controllable phosphidation of HWS Ni-Co-carbonates hydroxide precursor grown on Ni foam (NF). The experimental parameters were optimally tuned to understand the formation process of the precursor and to regulate the microstructure of the materials. The test results indicated that the HWS NiCoP/NF can produce a current density of 10 mA cm-2 (η10) at a low overpotential of 59 mV and a current density of 100 mA cm-2 (η100) at an overpotential of 220 mV for HER. Notably, upon surface activation with KOH, the HER performance of HWS NiCoP/NF could be dramatically enhanced with η10 and η100 values of 42 mV and 141 mV, respectively. The HWS NiCoP/NF showed a superior performance to NiCoP displaying other morphologies (sheets and wires etc.) The good performance of HWS NiCoP/NF should be attributed to their special whisker-on-sheet structures that are favourable for effective contact with the electrolyte. Also, hydrated metals can be formed on surface after the alkali treatment step, which is beneficial to moderate the bonding to hydrogen and thus, improve the HER activity. The present study will be indicative toward the construction of highly-efficient HER catalysts by regulating the structure of the materials.

Electrocatalytic oxidation of benzyl alcohol for simultaneously promoting H2 evolution by a Co0.83Ni0.17/activated carbon electrocatalyst

Co_0.83Ni_0.17 alloy nanoparticles on activated carbon were successfully fabricated by a simple thermal-treatment method, as electrocatalyst exhibiting superior HER, OER and electrocatalytic oxidation activity toward benzyl alcohol.