Nickel Foam Research Articles

Investigating the synergistic effects of NbCo-oxide composite electrodes in supercapacitor and water splitting applications via hydrothermal synthesis

A self-supported, binderless NbCo-oxide composite electrode was synthesized directly on a nickel foam (NF) substrate through a simple one-step hydrothermal process and utilized for energy storage and conversion applications. The optimized NbCo-oxide electrode displayed impressive energy storage capabilities, boasting an areal capacitance of 10.1 F/cm2 (equivalent to 9.10C/cm2), an energy density of 0.57 mWh/cm2, and a power density of 6.75 mW/cm2 at a 15 mA/cm2 current density. Furthermore, this electrode exhibited notable bifunctional activity, with low overpotentials of 217 mV for the hydrogen evolution reaction (HER) and 250 mV for the oxygen evolution reaction (OER) at a 10 mA/cm2 current density. The distinctive morphology, featuring rectangular blocks and plate-like microstructures, provided numerous exposed electro-active sites, facilitating efficient charge transfer, and enhancing overall electrochemical performance. The sturdy self-supporting structure on the NF substrate ensures remarkable stability, highlighting NbCo-composite materials' potential for energy storage and conversion.

Fabrication of a high-performance symmetrical supercapacitor based on electrochemically interconnected Cu:NiO@rGO:PANI/NF electrodes

A three-step electrodeposition synthesis was carried out to prepare a nanocomposite electrode of copper-doped nickel oxide and reduced graphene oxide-doped polyaniline with synergistic effects. Nickel foam was utilized as a current collector. XRD, FTIR and XPS studies confirm the molecular bond formation and molecular phase of the produced materials. According to the EDS results, the rGO:PANI/NF electrode contains 0.29 % nitrogen (N), 17.39 % carbon (C), and 9.81 % oxygen (O), while the Cu:NiO@rGO:PANI/NF electrode contains 8.24 % copper (Cu), 9.22 % carbon (C), 7.21 % oxygen (O), and 0.72 % nitrogen (N). The electrochemical performance of rGO:PANI/NF and Cu:NiO@rGO:PANI/NF electrodes were tested in a three-electrode cell with 3 M KOH aqueous electrolyte. High specific capacitances of 644.5 and 807.1 Fg−1 are achieved with the rGO:PANI/NF and Cu:NiO@rGO:PANI/NF electrodes at a current density of 20 Ag−1, respectively. The Cu:NiO@rGOPANI/NF also has a lower charge transfer resistance (RCT = 0.9 Ω) than the rGO:PANI/NF electrode (RCT = 3.8 Ω). This means NiO plays a crucial role in facilitating the transportation of charges between rGO:PANI. NiO acts as a “superhighway” that enables efficient and speedy charge transport. The expanded BET surface area of Cu:NiO@rGO:PANI/NF can be attributed to a well-interconnected network of PANI chains with NiO. In order to demonstrate a further application, an all-solid-state symmetrical supercapacitor (SSC) was then fabricated using the Cu:NiO@rGO:PANI/NF electrodes. The operating potential range is between 0 and 1.5 V. The device has a good capacitance of 81.9 Fg−1 at 4.5 Ag−1, and a capacitance retention of 97.6 % at a specific current of 10 Ag−1 after 10,000 cycles. The symmetrical device has a maximum energy density of 25.6 Wh kg−1 at a high power density of 1297.6 W kg−1 at 4.5 A g−1. In light of these results, the nanocomposite-based solid-state supercapacitor is considered to be a promising device for the development of high-performance symmetric supercapacitors.

Excellent sodium metal deposition enabled by three-dimensional porous structures with natrophilic Ni-Sn alloy

Na metal has long been an ideal potential anode material for sodium secondary batteries due to its own superiority; however, the Na dendrite problem during cycling makes it face a great obstacle in application. Here, we grow sodiophilic thin film materials with tin and nickel-tin components uniformly on three-dimensional nickel foam (3D-Ni) to obtain a 3D sodiophilic composite framework (namely 3D-NiSn) using a reproducible and mass-produced electrodeposition strategy. The combination of sodiophilic film (NiSn) and 3D porous framework could lower nucleation overpotential of Na and accelerate ions diffusion, hence inducing the uniform deposition and reversible stripping of sodium and inhibiting the growth of Na dendrites, which makes the 3D-NiSn/Na composite anode exhibit good performance compared to 3D-Ni/Na and Na-foil. The symmetrical cells with 3D-NiSn/Na can maintain up to 2500 h at 2 mA cm−2 and 1 mAh cm−2 with a low overpotential of around 30 mV during the whole cycling process. Additionally, the 3D-NiSn/NaǁNa3V2(PO4)3 full cells deliver good cycle stability with a high specific capacity of around 98.1 mAh g−1 at 3C for over 600 cycles. This work provides an idea for constructing low-cost and commercially available Na metal electrodes toward high-performance SIBs.

Heterointerface-Rich Ni3N/WO3 Hierarchical Nanoarrays for Efficient Glycerol Oxidation-Assisted Alkaline Hydrogen Evolution.

Glycerol oxidation-assisted water electrolysis has emerged as a cost-effective way of co-producing green hydrogen and HCOOH.Still, preparinghighly selective and stable nickel-based metal electrocatalysts remains a challenge. Herein, heterostructure Ni3N/WO3nanosheet arrays of bifunctional catalysts with large specific surface areas loaded on nickel foam (denoted as Ni3N/WO3/NF) were synthesized. This catalyst was for glycerol oxidation reaction (GOR) and hydrogen evolution reaction (HER) with excellent catalytic performance, a voltage saving of 267 mV compared to oxygen evolution reaction (OER), and a HER overpotential of 104 mV at 100 mA cm-2. The cell voltage in the assembled GOR // HER hybrid electrolysis system reaches 100 mA cm-2 at 1.50 V,296 mV lower than the potential required for overall water splitting. This work demonstrates that replacing GOR with OER using a cost-effective and highly active Ni-based bifunctional electrocatalyst can make hybrid water electrolysis an energy-efficient, sustainable, and green strategy for hydrogen production.

Facile Deposition of a Spherical Ruthenium–Cobalt Alloy on Nickel Foam as a High-Performance Electrocatalyst for Alkaline Hydrogen Production

Facile Deposition of a Spherical Ruthenium–Cobalt Alloy on Nickel Foam as a High-Performance Electrocatalyst for Alkaline Hydrogen Production

Application of TiO2 Supported on Nickel Foam for Limitation of NOx in the Air via Photocatalytic Processes

TiO2 was loaded on the porous nickel foam from the suspended ethanol solution and used for the photocatalytic removal of NOx. Such prepared material was heat-treated at various temperatures (400–600 °C) to increase the adhesion of TiO2 with the support. Obtained TiO2/nickel foam samples were characterized by XRD, UV–Vis/DR, FTIR, XPS, AFM, SEM, and nitrogen adsorption at 77 K. Photocatalytic tests of NO abatement were performed in the rectangular shape quartz reactor, irradiated from the top by UV LED light with an intensity of 10 W/m2. For these studies, a laminar flow of NO in the air (1 ppm) was applied under a relative humidity of 50% and a temperature of 28 °C. Concentrations of both NO and NO2 were monitored by a chemiluminescence NO analyzer. The adsorption of nitrogen species on the TiO2 surface was determined by FTIR spectroscopy. Performed studies revealed that increased temperature of heat treatment improves adhesion of TiO2 to the nickel foam substrate, decreases surface porosity, and causes removal of hydroxyl and alcohol groups from the titania surface. The less hydroxylated surface of TiO2 is more vulnerable to the adsorption of NO2 species, whereas the presence of OH groups on TiO2 enhances the adsorption of nitrate ions. Adsorbed nitrate species upon UV irradiation and moisture undergo photolysis to NO2. As a consequence, NO2 is released into the atmosphere, and the efficiency of NOx removal is decreasing. Photocatalytic conversion of NO to NO2 was higher for the sample heated at 400 °C than for that at 600 °C, although coverage of nickel foam by TiO2 was lower for the former one. It is stated that the presence of titania defects (Ti3+) at low temperatures of its heating enhances the adsorption of hydroxyl groups and the formation of hydroxyl radicals, which take part in NO oxidation. Contrary to that, the presence of titania defects in TiO2 through the formation of ilmenite structure (NiTiO3) in TiO2/nickel foam heated at 600 °C inhibits its photocatalytic activity. No less, the sample obtained at 600 °C indicated the highest abatement of NOx due to the high and stable adsorption of NO2 species on its surface.

Electrocatalytic Reforming of Polylactic Acid Plastic Hydrolysate over Dynamically Formed γ-NiOOH.

Upcycling plastic waste into valuable commodity chemicals with clean energy is an appealing strategy for mitigating environmental issues. Polylactic acid (PLA), a biodegradable plastic that is produced annually in millions of tons, can be chemically recycled to valuable products instead of being degraded to carbon dioxide. Here, we demonstrate an electrochemical reforming of PLA hydrolysate to acetate and acetonate using nickel phosphide nanosheets on nickel foam (Ni2P/NF) as the catalyst. The Ni2P/NF catalyst was synthesized by electrochemical deposition and phosphide treatment and showed excellent catalytic activity and ∼100% Faraday efficiency for electroreforming PLA to acetate and acetonate in an H-cell. Moreover, a stable performance of more than 90% Faraday efficiency for value-added organics was achieved for a duration of 100 h in a flow cell at a current density of 100 mA cm-2 and a potential below 1.5 V vs. RHE. In situ characterization revealed that the catalyst underwent electrochemical reforming during the reaction to produce γ-phase NiOOH with high electrochemical activity. This work introduces a new and green solution for the treatment of waste PLA, presenting a low-cost and highly efficient strategy for electrically reforming plastics.

Enhanced Electrochemical Performance in Supercapacitors through Cu-Cy Based Metal-Organic Framework Electrodes.

In the quest for advanced energy storage, the fusion of organic and metallic constituents has led to the development of a novel metal-organic polymer, synthesized from Cyamelurate and copper (Cu-Cy), for supercapacitor electrodes. This study presents the synthesis of Cu-Cy as a thin film on stainless steel grids and directly on nickel foam, followed by extensive characterization to confirm phase purity and investigate structural details. SCXRD and PXRD analyses affirmed the material's synthesis and crystalline purity, while FTIR provided chemical bond insights. TGA assessed thermal stability, revealing robustness suitable for electrochemical applications. Electrochemical testing via cyclic voltammetry showed that nickel foam-supported Cu-Cy electrodes, without binders, achieved a remarkable specific capacity of 1210.89 F/g at 5mV/s. In contrast, the stainless-steel grid electrodes, with binders and conductive agents, reached 363.73 F/g. Additionally, Cu-Cy demonstrated excellent cyclization resistance, maintaining 90% capacity after 11,000 cycles. These results highlight Cu-Cy potential as a superior electrode material for supercapacitors, especially in binder-free configurations, paving the way for its use in cutting-edge energy storage solutions.

Reversing the Interfacial Electric Field in Metal Phosphide Heterojunction by Fe-Doping for Large-Current Oxygen Evolution Reaction.

Developing non-precious-metal electrocatalysts that can operate with a low overpotential at a high current density for industrial application is challenging. Heterogeneous bimetallic phosphides have attracted much interest. Despite high hydrogen evolution reaction (HER) performance, the ordinary oxygen evolution reaction (OER) performance hinders their practical use. Herein, it is shown that Fe-doping reverses and enlarges the interfacial electrical field at the heterojunction, turning the H intermediate favorable binding sites for HER into O intermediate favorable sites for OER. Specifically, the self-supported heterojunction catalysts on nickel foam (CoP@Ni2P/NF and Fe-CoP@Fe-Ni2P/NF) are readily synthesized. They only require the overpotentials of 266 and 274mV to drive a large current density of 1000mA cm-2 (j1000) for HER and OER, respectively. Furthermore, a water splitting cell equipped with these electrodes only requires a voltage of 1.724V to drive j1000 with excellent durability, demonstrating the potential of industrial application. This work offers new insights on interfacial engineering for heterojunction catalysts.

Fabrication of nickel foam/MXene/CoAl-layered double hydroxide by electrodeposition as electrode material for high-performance asymmetric supercapacitor

Layered double hydroxides (LDH) have become one of the highly promising electrode materials due to large specific area, excellent cycling stability and high energy density. However, the large internal resistance limits their applications in energy storage. The introduction of highly conductive materials is expected to solve this problem. In here, nickel foam (NF)/MXene/CoAl-LDH is prepared by electrodepositing CoAl-LDH on the surface of MXene-coated NF, and the effects of Co:Al ratio on the electrochemical properties are investigated in detail. The best electrochemical performance of the composite is obtained when Co:Al=2:1, with a specific capacitance of 646.7 F g−1 at 0.5 A g−1 and 450.8 F g−1 at 5 A g−1. Furthermore, the asymmetric supercapacitor is assembled with NF/MXene/CoAl-LDH as the positive electrode and activated carbon (AC) as the negative electrode. The voltage window of the device can reach 1.6 V. The specific capacitance of the device is 126.87 F g−1 at a current density of 0.5 A g−1. At the power density of 400 W kg−1, the energy density of 45.11 Wh kg−1 is provided. Even at the high power density of 4000 W kg−1, the energy density can still reach 17.88 Wh kg−1. After 5000 cycles at a current density of 5 A g−1, it still maintains a capacity retention rate of 92.9%. The asymmetric device with its high specific capacitance, long term stability and good power density and energy density has a great potential in energy storage applications.

Surface functionalization of nickel foam with two-dimensional conjugated MOFs Fe3(hexaiminotriphenylene)2 for highly efficient oxygen evolution reaction

The design of high-efficient, low-cost, and stable electrocatalysts for oxygen evolution reaction (OER) is highly demanding for energy conversion applications. Metal-organic frameworks (MOFs), with large surface area and flexible molecular species, can supply atom-dispersed metal active coordination sites (M−NX, M−SX, M−OX) for OER and have been regarded as potential catalysts for practical applications. However, it is still challenging to use MOFs as OER catalysts directly due to their low conductivity and poor stability. Herein, we successfully synthesized a 2D c-MOF of Fe3(HITP)2 (HITP = 2,3,6,7,10,11-hexaiminotriphenylene) on the surface of nickel foam (NF) by using a layer-by-layer self-assembly strategy. The Fe3(HITP)2/NF-x electrode (x = 5, 10, 15, 20 is the number of cycles) exhibited impressive OER catalytic activity in alkaline electrolyte (1 M KOH), which is superior or comparable to most of the transition metal-based materials reported. Typically, Fe3(HITP)2/NF-15 were able to fully expose the Fe-N4 catalytic sites with an overpotential of 224 mV at a current density of 10 mA·cm−2 and a Tafel slope of 45.4 mV·dec-1. This was mainly attributed to the higher ECSA value, better kinetic process, and fast charge transfer ability of Fe3(HITP)2/NF. In addition, the current density of Fe3(HITP)2/NF-15 remained at 97.3 % of the initial current density after 24 h i-t stability test, showing excellent catalytic stability. This work provided a novel design strategy for the direct application of MOFs to OER applications.

Rational Design of Nanosheet Array-Like Layered-Double-Hydroxide-Derived NiCo2O4 In Situ Grown on Reduced-Graphene-Oxide-Coated Nickel Foam for High-Performance Solid-State Supercapacitors.

The investigation of high-performance supercapacitors is essential for accelerating the development of energy storage devices. In this work, a 3D hierarchical nanosheet array-like nickel cobaltite/reduced graphene oxide/nickel foam composite (NiCo2O4/rGO/NF) was assembled via an aqueous coprecipitation-hydrothermal strategy assisted by citric acid. Benefiting from a NiCo layered-double-hydroxide precursor with an atomic-level lattice confinement effect of metal ions and effective hybridization with rGO, the NiCo2O4/rGO/NF composite is featured as thin NiCo2O4 nanosheets (∼113.6 nm × 11.2 nm) composed of NiCo2O4 nanoparticles (∼10.9 nm) vertically staggered on the surface of a rGO-modified NF skeleton, leading to high surface area, abundant mesoporous structure, and active site exposure. The as-obtained NiCo2O4/rGO/NF was directly used as a binder-free integrated electrode for supercapacitors, achieving an excellent specific capacitance of 2863.4 F g-1 (1503.3 C g-1) at 1 A g-1, a superior rate performance of 2335.2 F g-1 at 20 A g-1, and a stability retention of 91.7% after 5000 cycles. More impressively, a solid-state asymmetric supercapacitor assembled by the present NiCo2O4/rGO/NF integrated electrode as the positive electrode and commercial activated carbon as the negative electrode achieved a high energy density of 69.2 Wh kg-1 at a power density of 800 W kg-1, and the energy density at a peak power density of 20004 W kg-1 still remained at 48.9 Wh kg-1, also showing a good cycling stability of 87.2% retention over 10000 cycles. The present facile synthesis strategy of the as-obtained NiCo2O4/rGO/NF nanosheet array composite can be used for the design and construction of many other transition-metal oxide/graphene/NF composite materials with excellent structural stability and performance in energy storage and other related areas.

Engineering of Self-Supported Electrocatalysts on a Three-Dimensional Nickel Foam Platform for Efficient Water Electrolysis

Engineering of Self-Supported Electrocatalysts on a Three-Dimensional Nickel Foam Platform for Efficient Water Electrolysis

Amorphous/Crystalline Phases Mixed Nanosheets Array Rich in Oxygen Vacancies Boost Oxygen Evolution Reaction of Spinel Oxides in Alkaline Media.

As promising oxygen evolution reaction (OER) catalysts, spinel-type oxides face the bottleneck of weak adsorption for oxygen-containing intermediates, so it is challenging to make a further breakthrough in remarkably lowering the OER overpotential. In this study, a novel strategy is proposed to substantially enhance the OER activity of spinel oxides based on amorphous/crystalline phases mixed spinel FeNi2O4 nanosheets array, enriched with oxygen vacancies, in situ grown on a nickel foam (NF). This unique architecture is achieved through a one-step millisecond laser direct writing method. The presence of amorphous phases with abundant oxygen vacancies significantly enhances the adsorption of oxygen-containing intermediates and changes the rate-determining step from OH*→O* to O*→OOH*, which greatly reduces the thermodynamic energy barrier. Moreover, the crystalline phase interweaving with amorphous domains serves as a conductive shortcut to facilitate rapid electron transfer from active sites in the amorphous domain to NF, guaranteeing fast OER kinetics. Such an anodic electrode exhibits a nearly ten fold enhancement in OER intrinsic activity compared to the pristine counterpart. Remarkably, it demonstrates record-low overpotentials of 246 and 315 mV at 50 and 500 mA cm-2 in 1 m KOH with superior long-term stability, outperforming other NiFe-based spinel oxides catalysts.

Low-temperature plasma-assisted synthesis of iron and nitrogen co-doped CoFeP-N nanowires for high-efficiency electrocatalytic water splitting

Designing efficient, stable, and low-cost non-precious metal electrocatalysts is critical for gainful utilization of renewable resources and effective water splitting. The catalytic efficiency is determined by interactions between the multiple main constituent elements and dopants. However, achieving performance-boosting synergistic interactions between different species in the catalyst is challenging. This work demonstrates such effect using low-temperature plasma-enhanced hydrothermal-phosphorization synthesis of Fe, N co-doped CoFeP-N nanowires. Nickel foam was utilized as the substrate to prepare CoFe-LDH precursor by hydrothermal method and CoFeP nanoparticles were obtained by phosphorization in a tube furnace. The N element was further doped into CoFeP using a low-temperature plasma discharge. The produced CoFeP-N nanowires exhibit far superior hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) activities in an alkaline medium compared to the original CoP due to the incorporation of Fe and N elements, with overpotentials of 64 mV and 219 mV at 10 mA cm−2 respectively, and excellent cycling stability. When CoFeP-N is used as both the cathode and anode of a two-electrode water splitting device, low voltages of only 1.516 V and 1.636 V were needed to achieve current density of 10 mA cm−2 and100 mA cm−2 respectively, which are better than that of Pt/C||RuO2 and most non-precious metal-based electrocatalysts reported to date. These experimental results provide new insights and strategies for developing efficient, stable, and low-cost bifunctional water splitting electrocatalysts.

CuCo2S4@MnO2 hollow porous heterostructure for high-performance supercapacitors

The design and synthesis of hollow porous heterostructures from multiple components is expected to impart excellent properties to the electrochemically active materials owing to their high internal voids, high surface area, and high pore volume, which are beneficial for electrolyte infiltration. However, the development of optimized electrode materials for hollow porous heterostructure storage fell behind expectations. To address these challenges, we prepared a CuCo2S4@MnO2 composite on a foam nickel substrate to create a hollow porous heterostructure. The optimized composite possesses high areal capacitance of 14.9 F cm−2 (or a specific capacitance of 1643 F g−1) at 3 mA cm−2, and 83.4% capacitance retention after 30,000 cycles in a three-electrode configuration. The NF@CuCo2S4@MnO2//AC asymmetric supercapacitor can achieve high energy density (1.2 mWh cm−2) and power density (2.4 mW cm−2) due to the wide cell voltage in aqueous electrolyte and high particular capacitances from both CuCo2S4 and MnO2 improved by the hollow porous heterostructure. Furthermore, the NF@CuCo2S4@MnO2//AC ASC can light up an LED display screen. Overall, this work demonstrates the great potential and broad prospects for application in energy storage of hollow porous heterostructures.

Fabrication of CoFe-LDH nanosheets@CoP nanowires hierarchical heterostructure with enhanced bifunctional electrocatalytic activity for alkaline water splitting

Exploring high active, low cost and stable electrocatalysts to replace noble precious metals has always been the major challenge in overall water splitting applications. Herein, CoFe-layered double hydroxide/Cobalt phosphide heterostructures on nickel foam (CoFe-LDH@CoP/NF) have been synthesized by using hydrothermal, chemical vapor deposition (CVD) and electrodeposition methods. The CoFe-LDH nanosheet is uniformly deposited on the surface of CoP nanowires to create the heterostructure. The formation of heterostructure increases active surface area, accelerates charge transfer velocity, optimizes the kinetics of reaction, thereby significantly improves electrocatalytic activity of the materials. The CoFe-LDH@CoP/NF attains 10 mA cm−2 with a low overpotential of 238 mV for OER and only 63 mV for HER. The catalyst provides the current density of 10 mA cm−2 throughout the overall water splitting by only requiring a low potential of 1.54 V. The CoFe-LDH@CoP/NF as an ideal electrocatalyst provides new ideas for developing efficient non-noble metal-based overall water splitting catalysts.

Novel hydrothermally synthesized NiS nanomaterial decorated over g-CN nanosheet for OER activity

The main objective of the present work is the fabrication of extremely efficient and new electrocatalysts for the water splitting process, which is important for producing clean energy. Cost-effective metal sulfides have demonstrated greater advantages over other materials for OER in an alkaline electrolyte. Despite extensive efforts, we have synthesized the innovative g-CN/NiSnanocomposite using a hydrothermal techniquefor electrocatalytic water splitting. We conducted a comprehensive set of tests toanalyze the electrocatalytic potential ofsynthesizedelectrocatalyst. Furthermore, the kinetic mechanisms of the produced electrocatalyst applied on nickel foam (NF)were investigated by linear sweep voltammetry (LSV). The chronoamperometry, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were employed to determine the stability and catalytic process using a basic (1.0 M KOH) solution. The electrochemical tests of g-CN/NiS nanocomposite exhibit an impressive overpotential 194 mV to achieve ideal current density (Cd) 10 mA cm−2 and have a lowest Tafel value (33 mV dec-1). In addition, compared to a reversible hydrogen electrode (RHE), the nanocomposite exhibits a decrease in onset potential by 1.42 V and has remarkable stability for a duration of 50 h. Hence, it is feasible to enhance electrochemical efficiency byaltering the shape and surface interactions. These features collectively indicate that the electrocatalyst is highly suitable for the OER process.

Nanostructured NiMoO4 electrode materials for efficient oxygen evolution reaction

Bifunctional electrocatalysts derived from earth-abundant transition metals are a promising substitute for noble metals in general water electrolysis, but their low activity and short durability limit their application. Herein, a nickel molybdate nanoparticles decorated on nickel foam (NiMoO4/NF NPs) electrode was fabricated by a facile hydrothermal method at three different time intervals (6, 12, and 24 h) and verified for the oxygen evolution reaction (OER). The constructed electrodes exhibited high OER activity in 1.0 M KOH with overpotentials of 315 mV, 290 mV and 320 mV for NiMoO4-6 h, NiMoO4-12 h, and NiMoO4-24 h, respectively. In addition, the NiMoO4-12 h electrodes displayed remarkable durability with a negligible reduction of 1.28 % at a current density of 10 mA cm−2 for 200 h. This research work delivers a new pathway to improve the electrocatalytic behaviour of the catalysts by synergistically moderating the inherent electrical conductivity, efficient surface moieties, and surface reaction.

VOx-doped CoP catalysts with synergistic dual-active configuration for boosting hydrogen evolution kinetics

Hydrogen evolution reaction (HER), is of great significance to harvest H2 via energy-saving alkaline water electrolysis yet still challenging. Integrating heterogeneous materials is effective in designing favorable electrocatalysts for water dissociation (WD) and H-immediate involved adsorption/desorption behavior and triggering positive interactions to break the kinetics limitation. Herein, a promising configuration of a vanadium-oxide species integrated with cobalt-phosphide plane that grown on the nickel foam (labeled as VOx-CoP/NF), is demonstrated to boost the alkaline HER kinetics comprehensively. The doped vanadium-oxide species preferentially perform the WD process to generate H-intermediates. Meanwhile, interaction between VOx and CoP induce the electronic redistribution that optimizes 3d-2p orbital hybridization state, which balances the adsorption strength of H* to facilitate the hydrogen transfer and enrichment. Eventually, VOx-CoP/NF exhibits supereminent alkaline HER performance with an overpotential of only 65/245mV at 10/400mAcm−2, superior to individual CoP and most representative cobalt-phosphide candidates. A flowing anion exchange membrane (AEM) urea-assisted water electrolyzer with VOx-CoP/NF as a bifunctional catalyst, is assembled and achieves a satisfactory performance, verifying its practical feasibility for efficient H2 production. The concept exemplified in this work is that synchronous optimization of elementary reaction step kinetics of HER through reasonable constructing well-defined configuration is instructive for the design of HER electrocatalysts.