Catalytic Activity For Hydrogen Evolution Reaction Research Articles

Bimetallic Nitride Ni3Mo3N Microrods with Abundant Catalytic Sites Used as Efficient Electrocatalysts for Hydrogen Evolution Reaction

Abstract The importance of efficient and stable hydrogen evolution reaction (HER) electrocatalysts for hydrogen production in alkaline conditions to energy crisis resolution and environmental pollution is immense. In general, the quantity of catalytic sites in the electrocatalyst limits the current density of HER. In response to such problems, the bimetallic effect of non-noble bimetallic nitrides has been shown to regulate the corresponding catalytic sites. Here, a microrod-like non-noble bimetallic nitride catalyst with Ni3Mo3N microrods uniformly modified on nickel foam was synthesized by hydrothermal and nitriding processes. The catalyst showed high catalytic activity for HER in 1M KOH solution. The overpotential was only 28 mV at a current density of 10 mA·cm-2, demonstrating exceptional electrochemical performance. Furthermore, it exhibited remarkable long-term stability under the same current density. This work will open up a low-cost and simple way for the synthesis of bimetallic nitrides as functional electrode materials for HER and electrochemical detection.

Different M-doped Ni3S2/FeS (M=Co, Cr, Cu, Zn) hybrid nanosheet arrays for overall urea splitting and seawater oxidation reaction

Hydrogen production by electrolysis of water is gradually becoming the main way to obtain green energy, but due to the scarcity of fresh water resources in the world, so the study of urea and seawater electrolysis has become an important work. In this experiment, different metal ions M (M=Co, Cr, Cu, Zn) doped Ni3S2/FeS were investigated as catalysts with good catalytic activity in hydrogen evolution reaction (HER) as well as in urea oxidation reaction (UOR) in urea electrolyte, and Co-Ni3S2/FeS and Cr-Ni3S2/FeS, which performed well in HER and UOR, were assembled into an electrolytic cell for the overall urea decomposition (1.50 V @ 10 mA cm−2). Density Functional Theory (DFT) calculations demonstrated that Co-Ni3S2 possesses a lower free energy for H, while FeS possesses a higher density of states (DOS) near the Fermi energy level, and such a composite structure promotes significantly the catalytic activity of HER. The catalytic effect of oxygen evolution reaction (OER) was further investigated in the seawater electrolyte, and the results showed that the performance of Co-Ni3S2/FeS catalyst was better, and certain ions in seawater affected durability of the catalyst. The electronic structure of the catalyst was investigated through the characterization of the catalyst and combined with the special morphology jointly promote the catalytic reaction in electrolysis experiments, which provides a candidate catalyst for electrolysis of urea and seawater oxidation reaction.

Efficient Hydrogen Evolution Electrocatalyst: MoN/Ni3N/NF Coupled with Methanol Oxidation Reaction for Formate Production in Alkaline Media

Abstract Electrocatalytic water splitting for hydrogen production is promising, but its practical application is limited by the sluggish kinetics of the anodic oxygen evolution reaction (OER) and the less valuable oxygen by-product. Hence, replacing OER with a thermodynamically favorable methanol oxidation reaction (MOR) and coupling with value-added formate generation on the anode is an energy-saving and effective scheme. In this work, we report a self-supporting bifunctional electrocatalyst MoN/Ni3N/NF, which exhibits excellent hydrogen evolution reaction catalytic activity and stability, requiring overpotentials of only 18 and 68 mV to reach current densities of −10 and −100 mA cm−2, respectively. Moreover, the catalyst’s performance minimally deteriorates after long-standing chronopotentiometry measurements (−100 mA cm−2@150h). When MOR is used instead of OER, the required potential drops by 200 mV to 1.38 V at a current density of 100 mA cm−2 and MoN/Ni3N/NF also demonstrates splendid catalytic stability towards OER and MOR. Finally, a two-electrode system employing MoN/Ni3N/NF as a bifunctional electrocatalyst only requires a cell voltage of 1.40, 1.68 V to achieve current densities of 10 and 100 mA cm−2, respectively. The coupled electrolyzer also exhibits high faradaic efficiency for producing cathodic H2 (100%) and anodic formate (90%).

Exploration of transition metal atom-doped NiSe2 electrocatalysts for efficient alkaline hydrogen precipitation using first principles screening

Transition metal (TM) doping exhibits great potential in designing high-performance two-dimensional (2D) NiSe2-based catalysts for electrocatalytic hydrogen evolution reaction (HER). 22 TM atom-doped 2D-NiSe2 catalysts are screened, and the effects of TM doping on the thermal stability and HER catalytic activity are investigated by first-principles calculations. Among them, Cu doped 2D-NiSe2 might exhibit remarkable HER properties with the water dissociation energy of 1.03 eV and H adsorption Gibbs free energy of −0.05 eV. Furthermore, we elucidate the reasons behind the different HER activities. These findings suggest new possibilities for the application of Cu doped 2D-NiSe2 for alkaline HER, offering new perspectives for future research.

Synchronously integration of carbon-quantum-dot and Cu, Mo dual-metal doped in Ni3S2@Ni foam toward robust and stable electrocatalytic hydrogen generation

In the pursuit of advancing the production of H2 through hydrogen-evolution reaction (HER), the demand for the elaborate design of cost-effective and robust durability electrocatalysts has gained momentum, especially replacement of noble-metal counterparts like Pt. Herein, we introduce a facile one-pot hydrothermal approach to synthesize nickel foam-supported Ni3S2 nanosheet arrays, which integrate with carbon-quantum-dot (CQDs) and Cu, Mo dual-metal doped. With the introduction of CQDs and Cu, Mo dual-metal doped site, the optimal CQDs-Cu-Mo-Ni3S2@NF exhibits superior HER catalytic activity with a low overpotential of 125 mV at 10 mA cm-2 and strong durability for 30 h in alkaline medium. The exceptional electrocatalytic performance is ascribed to the synergistic effect of CQDs and Cu, Mo dual-metal site. This synergy encompasses optimization of water molecule adsorption/desorption energetics, elevated electrical conductivity, weakening of the strong S-H bond interaction on the Ni3S2 surface, and providing ample active centers. Furthermore, an in-depth understanding of the electronic structure and adsorption energy during the HER process is probed by density functional theory (DFT) analysis. Our work provides a quintessential paradigm for the rational design of multi-component electrocatalysts for water splitting.

Superior MoTiN and NiMoTiN coating electrode with platinum-like catalytic activity fabricated by plasma electrolytic oxidation

Electrolyzing water is an effective and feasible technology to achieve a large-scale hydrogen production in industry. However, it is still challenging to develop an efficient approach to fabricate a superior and stable hydrogen evolution reaction (HER) electrodes with low cost and outstanding catalytic efficiency. This work presents an innovative surface modification technique of plasma electrolytic oxidation (PEO) to fabricate superior MoN based coating electrodes. By simply introducing Na2MoO4 and NiAc2 into the electrolyte, a novel MoTiN and NiMoTiN coatings were successfully achieved on the surface of a titanium substrate by PEO and annealing treatments, which exhibits excellent mechanical adhesion and platinum-like catalytic properties. Importantly, it has been demonstrated that the newly formed MoTiN solid solution combined by active Mo2N and conductive TiN can contribute the superior catalytic activity and the subsequent Ni doping can effectively stabilize the structure and activity of MoTiN. Under the alkaline environment of 1 M KOH, the MoTiN and NiMoTiN coated electrodes require only 126 and 121 mV overpotential, respectively, to achieve a current density of 10 mA cm−2. Additionally, under the same test conditions, NiMoTiN can operate stably for over 24 h, demonstrating excellent HER catalytic activity and stability. This work provides new insights into the preparation of HER electrodes with superior mechanical properties and excellent catalytic performance towards industrial hydrogen production.

Efficient optimization of electron transfer pathway by constructing phosphide/ceria interface boosts seawater hydrogen production

Developing efficient and durable hydrogen evolution reaction (HER) electrocatalysts is one of the most important issues for the commercialization of seawater electrolysis, but it remains challenging. Here, we report a CeO2-CoP nanoneedle array catalyst loaded on Ti mesh (CeO2-CoP/TM) with work-function-induced directional charge transport properties. The CeO2-CoP/TM catalyst showed superior HER catalytic activity and stability, with overpotentials of 41 and 60 mV to attain 10 mA cm−2, in 1 M KOH and 1 M KOH + seawater electrolyte, respectively. Experimental results and theoretical calculations reveal that the work function drives the charge transfer from CeO2 to CoP, which effectively balances the electronic density of CoP and CeO2, optimizes the d-band center, and accelerates the water activation kinetics, thus enhancing the HER activity. The solar-driven water electrolysis device displays a high and stable solar-to-hydrogen conversion efficiency of 19.6%. This study offers a work function-induced directional charge transport strategy to design efficient and durable catalysts for hydrogen production.

Nitrogen-doped MoO2/Cu heterojunction electrocatalyst for highly efficient alkaline hydrogen evolution reaction

Metal/metal-(hydr)oxide heterojunction has been proposed as an efficient means to enhance the kinetics of alkaline hydrogen evolution reaction (HER). However, the poor electronic conductivity of metal-(hydr)oxides hinders the transport of electrons and the inappropriate electronic structure of the constituent phases would lower the HER activity. Herein, a nitrogen-doped MoO2/Cu heterostructure nanosheets was prepared by a simple hydrothermal and subsequent annealing treatment, acting as a model catalyst for element-doped modified metals/metal-oxides composite towards alkaline HER. Experimental results revealed that the HER catalytic activity of the catalyst was effectively improved by the nitrogen doping and the hetero coupling effect. The obtained N–MoO2/Cu catalyst exhibited a low overpotential of 40 and 363 mV to drive the current densities of 10 and 1000 mA cm−2, respectively, and showed high stability in the constant-current test of 50 h at 10 mA cm−2, 100 mA cm−2 and 1000 mA cm−2. Impressively, the N–MoO2/Cu catalyst coupled with Ni–Fe LDH to assemble an alkaline electrolyzer only require a voltage of 1.49 V to achieve a current density of 10 mA cm−2, and could be actuated by wind power to continuously produce hydrogen.

Improving the Efficiency of Water Splitting and Oxygen Reduction Via Single‐Atom Anchoring on Graphyne Support

Single‐atom catalysts (SACs) have received significant interest for optimizing metal atom utilization and superior catalytic performance in hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR). In this study, we investigate a range of single‐transition metal (STM1 = Sc1, Ti1, V1, Cr1, Mn1, Fe1, Co1, Ni1, Cu1, Zr1, Nb1, Mo1, Ru1, Rh1, Pd1, Ag1, W1, Re1, Os1, Ir1, Pt1, and Au1) atoms supported on graphyne (GY) surface for HER/OER and ORR using first‐principle calculations. Ab initio molecular dynamics (AIMD) simulations and phonon dispersion spectra reveal the dynamic and thermal stabilities of the GY surface. The exceptional stability of all supported STM1 atoms within the H1 cavity of the GY surface exists in an isolated form, facilitating the uniform distribution and proper arrangement of single atoms on GY. In particular, Sc1, Co1, Fe1, and Au1/GY demonstrate promising catalytic efficiency in the HER due to idealistic ΔGH* values via the Volmer‐Heyrovsky pathway. Notably, Sc1 and Au1/GY exhibit superior HER catalytic activity compared to other studied catalysts. Co1/GY catalyst exhibits higher selectivity and activity for the OER, with an overpotential (0.46 V) comparable to MoC2, IrO2, and RuO2. Also, Rh1 and Co1/GY SACs exhibited promising electrocatalysts for the ORR, with an overpotential of 0.36 and 0.46 V, respectively. Therefore, Co1/GY is a versatile electrocatalyst for metal‐air batteries and water‐splitting. This study further incorporates computational analysis of the kinetic potential energy barriers of Co1 and Rh1 in the OER and ORR. A strong correlation is found between the estimated kinetic activation barriers for the thermodynamic outcomes and all proton‐coupled electron transfer steps. We establish a relation for the Gibbs free energy of intermediates to understand the mechanism of SACs supported on STM1/GY and introduce a key descriptor. This study highlights GY as a favorable single‐atom support for designing highly active and cost‐effective versatile electrocatalysts for practical applications.

A versatile heterostructure junction of NiO–C-MoOx (X= 2 & 3) composite electrocatalysts for hydrogen evolution reaction

Developing high-density crystal heterostructure interfaces is highly desirable for the hydrogen evolution reaction (HER). For the first time, NiO-modified MoOx heterogeneous structures are created on carbon matrix materials using a solid-state reaction of the precursor. The solid-state reaction method uses a novel concept called “solid solvent” instead of many solvents and is simple, scalable, and less harmful to the environment. The NiO–C–MoO2 catalyst has an active surface of 40.1 m2 g−1. The NiO–C–MoO2 compound showed superior hydrogen evolution reaction (HER) performance compared to NiO–C–MoO3, with a low overpotential of only 170 mV and Tafel slope of 81.1 mV dec−1 vs. reverse hydrogen electrode (RHE). The d-band structure and modulated charge close to the Fermi level are responsible for the enhanced conductivity, increased availability of active sites, and advantageous H+ adsorption sites. This underscores the significance of optimizing the electronic structure of bifunctional electrocatalysts based on transition metals for optimal HER catalytic activity.

On the use of WO42− as a third component to Co–Mo ionic activator for HER in alkaline water electrolysis

This study investigates the impact of Co–Mo–W ionic activators on the hydrogen evolution reaction (HER) in alkaline electrolysis, comparing their performance to Co–Mo and Co–W systems. The research focuses on analyzing the catalytic efficiency of these activators under varying conditions, including temperature and current density variations. Key findings reveal that the Co–Mo–W activator enhances HER performance, with a significant 17% reduction in energy consumption compared to plain electrolyte, mirroring the efficiency of Co–Mo. Tafel analysis gave the insight of the reaction mechanism for HER for all activators, with Co–Mo–W exhibiting a lower Tafel slope, suggesting improved catalytic activity. Structural and morphological analysis of electrode coatings shows a highly developed surface for Co–Mo–W, with a roughness factor similar to or slightly lower than the most developed Co–Mo coating. The study concludes that the synergistic combination of Co, Mo, and W in a tri-component ionic activator offers a promising catalytic activity for HER, outperforming bi-component systems and presenting significant potential for industrial-scale alkaline water electrolysis applications.

Theoretical and experimental study of flower-like NiMoS/NiO/NF with interface layer as a novel highly efficient bifunctional-electrode toward supercapacitor and HER

Electrocatalytic water splitting and supercapacitor systems are considered one of the most imperative sustainable energy storage and conversion technologies as an alternative clean energy carrier/source to fossil fuels in order to address the pressing global warming problems. For achieving sustainable electrochemistry devices, highly efficient and superior durability electrocatalysts must be prepared through a facile and controllable approach. This study successfully demonstrated the development of a binder-free 3D- flower-like amorphous structure composite with self-assembled nanosheets supported on Nickel foam (NiMoS/NiO/NF) by a simple two-step hydrothermal technique as advanced electrocatalysts for alkaline hydrogen evolution reaction (HER) and supercapacitor. The as-obtained NiMoS/NiO/NF only needs a overpotential of 43 mV vs. RHE to reach 10 mA.cm−2 and remained stable after long-term HER tests. In the following, the nanostructure was operated as an electrode in the supercapacitor. According to the Galvanostatic Charge-Discharge (GCD) teats, the specific capacitance of NiMoS/NiO/NF was measured as 999F/g. Such outstanding NiMoS/NiO/NF performance can be ascribed to the synthesis of the interface layer (NiO), which makes the robust adhesion between NF and the final layer (NiMoS). The amorphous morphology with multi-component doping and heterojunctions, optimizes the hydrogen desorption sites, which leads to significant HER catalytic activity. The present experimental results and density functional theory (DFT) study offer a cost-effective, and convenient pathway to produce highly efficient non-nobel-based metal as high-valued multifunctional materials.

Toward boosted alkaline hydrogen evolution reaction: Covalent organic framework-derived N-doped carbon for highly dispersed cobalt nanoparticles

The preparation of renewable hydrogen via electrocatalytic water splitting is a burgeoning strategy in developing sustainable energy. However, it is still a great challenge to prepare an efficient non-precious metal based electrocatalyst for hydrogen evolution in alkaline electrolysis. Herein, we describe a functional hydrogen evolution reaction (HER) electrocatalyst by the combination of soaking metal ions in covalent organic framework (COF) and high temperature calcination. Especially, the 2Co-NC-700 catalyst possesses large specific surface area, appropriate defective nature and structural distortion, thus it embodies outstanding HER catalytic activity with only an overpotential of 303 mV at the current density of 10 mA cm−2 in the solution of 1.0 M KOH. Moreover, the kinetics and durability are also confirmed. Theoretical calculations not only indicates that the stable configuration combined small-sized cobalt nanoparticles and nitrogen-doped carbon but also reveals the synergistic effect of multiple active sites, while the optimal active location that shows the lowest hydrogen adsorption free energy is a major contributor for excellent HER. This work not only offers a highly efficient HER catalyst in alkaline environment but also provides a novel approach to develop non-precious metal nitrogen-doped carbon materials derived from COF as HER electrocatalysts in alkaline media.

Constructing Amorphous-Crystalline Interfacial Bifunctional Site Island-Sea Synergy by Morphology Engineering Boosts Alkaline Seawater Hydrogen Evolution.

The development of efficient and durable non-precious hydrogen evolution reaction (HER) catalysts for scaling up alkaline water/seawater electrolysis is highly desirable but challenging. Amorphous-crystalline (A-C) heterostructures have garnered attention due to their unusual atomic arrangements at hetero-interfaces, highly exposed active sites, and excellent stability. Here, a heterogeneous synthesis strategy for constructing A-C non-homogeneous interfacial centers of electrocatalysts on nanocages is presented. Isolated PdCo clusters on nanoscale islands in conjunction with Co3 S4 A-C, functioning as a bifunctional site "island-sea" synergy, enable the dynamic confinement design of metal active atoms, resulting in excellent HER catalytic activity and durability. The hierarchical structure of hollow porous nanocages and nanoclusters, along with their large surface area and multi-dimensional A-C boundaries and defects, provides the catalyst with abundant active centers. Theoretical calculations demonstrate that the combination of PdCo and Co3 S4 regulates the redistribution of interface electrons effectively, promoting the sluggish water-dissociation kinetics at the cluster Co sites. Additionally, PdCo-Co3 S4 heterostructure nanocages exhibit outstanding HER activity in alkaline seawater and long-term stability for 100h, which can be powered by commercial silicon solar cells. This finding significantly advances the development of alkaline seawater electrolysis for large-scale hydrogen production.

Assembly of amorphous CoP electrocatalysts on flexible polyester textile for alkaline hydrogen evolution reaction

The design of low-price and flexible hydrogen evolution reaction (HER) electrode has attracted much attention on efficient utilization of sustainable hydrogen energy. Herein, we reported a facile fabrication of flexible HER electrode by anchoring CoP electrocatalyst on polyester (PET) textiles. Conductive nickel cloth (NC-PET) substrate was firstly obtained by sequentially electroless plating and electroplating of metallic Ni on textile fibers. The amorphous CoP catalyst was then assembled on the NC-PET substrate by controlled electrodeposition to obtain flexible HER electrode (CoP-NC/PET). The flexible CoP-NC/PET showed a low overpotential of 63 mV at 10 mA cm−2 for HER, with a Tafel slope of 48.09 mV dec−1 in 1 M KOH solution. The faradaic efficiency of CoP-NC/PET measured at 100 mA cm−2 current density was estimated to be nearly 100%. No significant loss of HER catalytic activity was observed after 2000 cycles and 1000 times folding operations, demonstrating the high flexibility and stability of the present CoP-NC/PET electrode.

Multiscale confinement nitridation in molybdenum carbide for efficient hydrogen production

The molybdenum carbide (Mo2C) has been regarded as one of the most cost-efficient and stable electrocatalyst for the hydrogen evolution reaction (HER) by the virtue of its Pt-like electronic structures. However, the inherent limitation of high density of empty valence band significantly reduces its catalytic reactivity by reason of strong hydrogen desorption resistance. Herein, we propose a multiscale confinement synthesis method to design the nitrogen-rich Mo2C for modulating the band structure via decomposing the pre-coordination bonded polymer in a pressure-tight tube sealing system. Pre-bonded C/N-Mo in the coordination precursor constructs a micro-confinement space, enabling the homogeneous nitrogenization in-situ happened during the formation of Mo2C. Simultaneously, the evolved gases from the precursor decomposition in tube sealing system establish a macro-confinement environment, preventing the lattice N escape and further endowing a continuous nitridation. Combining the multiscale confinement effects, the nitrogen-rich Mo2C displays as high as 25% N-Mo concentration in carbide lattice, leading to a satisfactory band structure. Accordingly, the constructed nitrogen-rich Mo2C reveals an adorable catalytic activity for HER in both alkaline and acid solution. It is anticipated that the multiscale confinement synthesis strategy presents guideline for the rational design of electrocatalysts and beyond.

Boosting hydrogen evolution kinetics of self-supported MoC-Mo2C heterojunction electrode by platinum decoration

Molybdenum carbide-based hydrogen evolution reaction (HER) electrocatalysts have attracted widespread attention with their low cost and relatively high catalytic activity. Despite the significant progress made in tuning the morphology and structure, the intrinsic catalytic activity of molybdenum carbide awaits further improvement. Herein, a Pt-decorated self-supported MoC-Mo2C electrode with super-intrinsic HER catalytic activity is prepared by a simple adsorption-electroreduction method. The HER performance is improved with increasing the loading of Pt. The optimal MoC-Mo2C-Pt heterojunction electrode has a low overpotential of 10 mA cm−2 (58 mV in H2SO4, 82 mV in KOH) and small Tafel slope (24 mV dec−1 in H2SO4, 29 mV dec−1 in KOH), which is reduced to 0.45–0.5, 0.7–0.8, and 0.4–0.7 times of pristine MoC-Mo2C, Pt foil, and commercial Pt/C (2 mg cm−2), respectively. The improved HER catalysis is attributed to the rapid dissociation of water on MoC-Mo2C and efficient desorption of hydrogen on Pt. Therefore, decorating carbides with Pt is an effective way to design HER catalysts with enhanced catalytic activities in a wide pH range.

Synergistically coupling of ultrathin Ni3N layer with Ti3C2Tx-MXene nanosheets for efficient benzyl alcohol oxidation reactions and hydrogen production

The coupling of electrocatalytic benzyl alcohol (Ph-CH2OH) oxidation with the hydrogen evolution reaction (HER) has emerged as a promising approach to increase the overall efficiency of hydrogen production. However, designing bifunctional electrocatalysts with both high activity and selectivity remains a significant challenge. In this study, we introduce a new strategy for constructing ultrathin Ni3N nanosheets coupled with MXene using a cyanogel synthetic approach. Benefiting from the abundant catalytic sites in ultrathin Ni3N nanosheets, and the unique hydrophilicity and high conductivity of MXene, the MXene/Ni3N electrode demonstrates exceptional electrocatalytic Ph-CH2OH oxidation activity, achieving a 97.6 % selectivity towards benzoic acid (Ph-COOH) and a remarkable 95.6 % faradaic efficiency (FE). Notably, in weakly alkaline electrolytes, MXene/Ni3N nanocomposites can selectively produce benzaldehyde (Ph-CHO). Moreover, the MXene/Ni3N nanocomposites also show excellent catalytic activity for HER, exhibiting a low overpotential of 147 mV at 10 mA cm−2. This work presents a viable strategy for developing advanced, dual-function electrocatalysts.

Polyaniline nanowires decorated nickel phosphides hollow spheres hydrogen evolution catalyst for proton exchange membrane electrolysis

Cost-competitive proton exchange membrane water electrolyzer (PEMWE) requires efficient and earth-abundant electrocatalyst to replace Platinum for hydrogen evolution reaction (HER). We report here a polyaniline (PANI) nanowires decorated Ni2P hollow spheres catalyst and its exceptional activity toward HER in 0.5 M H2SO4 aqueous and PEMWE. The excellent catalytic activity of HER originates from unique hybrid structure of PANI/Ni2P with good conductivity, decent surface activity and optimal porous property. As a cheaper alternative to Pt/C, we used PANI/Ni2P as the cathode to set a PEMWE cell (Nafion® 117 membrane), the cell showed a current density of 1.0 A cm−2 at 1.822 V and 2.0 A cm−2 at 2.026 V, which is comparable with Pt/C (1.778 V at 1.0 A cm−2, and 2.086 V at 2.0 A cm−2). Our catalyst maintained a stable performance in a PEM electrolysis at a current density of 1.0 A cm−2 with the temperature of 80 °C, and preserved surface morphology and electron state well after 320 h continuous electrolysis. This study offers PANI/Ni2P HER catalyst as a cheaper replacement for Pt/C in PEMWE and provides a new insight to design earth-abundant catalysts for HER.

First-principles study of the electronic and catalytic properties of nickel-antimony (Ni-Sb) alloy catalyst for hydrogen evolution reaction

Hydrogen evolution reaction (HER) is a vital half-reaction for water splitting to produce H2. Exploring efficient, affordably priced, and environmentally sustainable HER catalysts is necessary for the development of renewable energy conversion and storage technologies. Here, the HER catalytic activity of hexagonal NiSb(010), hexagonal NiSb(001), hexagonal NiSb(101), cubic Ni3Sb(100), cubic Ni3Sb(010), cubic Ni3Sb(101), orthorhombic Ni3Sb(010), and orthorhombic Ni3Sb(101), is systematically investigated by density functional theory methods. Based on the calculated surface energy, all the studied surfaces are stable. Subsequently, we further evaluate their HER activity by calculating Gibbs free energy of hydrogen adsorption (ΔG*H) and exchange current density (i0). The results show that hexagonal NiSb and orthorhombic Ni3Sb are expected to be promising HER catalysts in Ni-Sb alloys because their ΔG*H values are respectively −0.03 and 0.03 eV, and they have larger i0 values. The synergistic interaction between the metal atoms of Ni and Sb can effectively promote electron transfer between the catalyst and reaction species, which is clearly demonstrated by the electronic structure analysis, which also illustrates that such high catalytic activity can be attributed to it. This work is conducive to guiding the design of this kind of alloy electrocatalysts for HER.