Topological Formation of a Mo-Ni-Based Hollow Structure as a Highly Efficient Electrocatalyst for the Hydrogen Evolution Reaction in Alkaline Solutions

Alloy Reconstruction in Pyrolytic Bowknot-like Heteronuclear CoFe Clusters for Electrocatalytic Application

The construction of doped molecular clusters is an intriguing way to perform bimetallic doping for electrocatalysts. However, efficiently harnessing the benefits of a doping strategy and alloy engineering to create a nanostructure for electrocatalytic application at the molecular level has consistently posed a challenge. Here we propose an in situ reconstruction strategy aimed at producing an alloy nanostructure through a pyrolysis process, originating from bowknot-like heterometallic clusters. The Schiff base, denoted as ligand L1 (o-vanillin ethylenediamine), was introduced as a precursor to coordinate Fe and Co metals, thereby yielding a heteronuclear metal cluster [(FeCo)(L1)2O]CH3CN. Subsequently, a comprehensive investigation of the in situ reconstruction process [(FeCo)(L1)2O](CH3CN) → [(FeCo)(L1)2O] → [M-O-M/M-O] [CH3+/CH3O+/H2C═N/C2H5+/C4H4+] → [FeCo/Fe3O4/Fe2O3/Co3O4][carbon layer] led to the formation of MOx/CoFe@NC-700 during the pyrolysis. This process reveals that the metals Fe and Co in the clusters undergo partly in situ evolution into FeCo alloys, resulting in the successful preparation of MOx/CoFe@NC (M = Fe, Co) nanomaterials that leverage the advantages of both doping strategies and alloy engineering. The synergistic interaction between alloy particles and metal oxides establishes active sites that contribute to the excellent oxygen evolution (OER) and hydrogen evolution (HER) catalytic behaviors. Notably, these materials exhibit outstanding OER and HER properties under alkaline conditions, with overpotentials of 191 and 88 mV for OER and HER, respectively, at 10 mA cm-2. Investigation of the in situ conversion of Schiff base bimetal clusters into alloy materials through pyrolysis offers a novel strategy for advancing electrocatalytic applications.

A universal method to fabricate high-valence transition metal-based HER electrocatalysts and direct Raman spectroscopic evidence for interfacial water regulation

Valence modulation of transition metal oxides represents a highly effective approach in designing high-performance catalysts, particularly for pivotal applications such as the hydrogen evolution reaction (HER) in solar/electric water splitting and the hydrogen economy. Recently, there has been a growing interest in high-valence transition metal-based electrocatalysts (HVTMs) due to their demonstrated superiority in HER performance, attributed to the fundamental dynamics of charge transfer and the evolution of intermediates. Nevertheless, the synthesis of HVTMs encounters considerable thermodynamic barriers, which presents challenges in their preparation. Moreover, the underlying mechanism responsible for the enhancement in HVTMs still needs to be discovered. Hence, the universal synthesis strategies of the HVTMs are discussed, and direct Raman spectroscopic evidence for intermediates regulation is revealed to guide the further design of the HVTM electrocatalysts. This work offers new insights for facile designing of HVTMs electrocatalysts for energy conversion and storage through adjusting the reaction pathway.

Composite MAX phase/MXene/Ni electrodes with a porous 3D structure for hydrogen evolution and energy storage application

MXenes, a family of two-dimensional (2D) transition metal carbides, have been discovered as exciting candidates for various energy storage and conversion applications, including green hydrogen production by water splitting. Today, these materials mostly remain interesting objects for in-depth fundamental studies and scientific curiosity due to issues related to their preparation and environmental stability, limiting potential industrial applications. This work proposes a simple and inexpensive concept of composite electrodes composed of molybdenum- and titanium-containing MAX phases and MXene as functional materials. The concept is based on the modification of the initial MAX phase by the addition of metallic Ni, tuning Al- and carbon content and synthesis conditions, followed by fluoride-free etching under alkaline conditions. The proposed methodology allows producing a composite electrode with a well-developed 3D porous MAX phase-based structure acting as a support for electrocatalytic species, including MXene, and possessing good mechanical integrity. Electrochemical tests have shown a high electrochemical activity of such electrodes towards the hydrogen evolution reaction (HER), combined with a relatively high areal capacitance (up to 10 F cm-2).

Electrocatalytic Lignin Valorization into Aromatic Products via Oxidative Cleavage of Cα-Cβ Bonds

Lignin is the most promising candidate for producing aromatic compounds from biomass. However, the challenge lies in the cleavage of C-C bonds between lignin monomers under mild conditions, as these bonds have high dissociation energy. Electrochemical oxidation, which allows for mild cleavage of C-C bonds, is considered an attractive solution. To achieve low-energy consumption in the valorization of lignin, the use of highly efficient electrocatalysts is essential. In this study, a meticulously designed catalyst consisting of cobalt-doped nickel (oxy)hydroxide on molybdenum disulfide heterojunction was developed. The presence of molybdenum in a high valence state promoted the adsorption of tert-butyl hydroperoxide, leading to the formation of critical radical intermediates. In addition, the incorporation of cobalt doping regulated the electronic structure of nickel, resulting in a lower energy barrier. As a result, the heterojunction catalyst demonstrated a selectivity of 85.36% for cleaving the Cα-Cβ bond in lignin model compound, achieving a substrate conversion of 93.69% under ambient conditions. In addition, the electrocatalyst depolymerized 49.82 wt% of soluble fractions from organosolv lignin (OL), resulting in a yield of up to 13 wt% of aromatic monomers. Significantly, the effectiveness of the prepared electrocatalyst was also demonstrated using industrial Kraft lignin (KL). Therefore, this research offers a practical approach for implementing electrocatalytic oxidation in lignin refining.

Scalable production of foam-like nickel-molybdenum coatings via plasma spraying as bifunctional electrocatalysts for water splitting

Foam-like NiMo coatings were produced from an inexpensive mixture of Ni, Al, and Mo powders via atmospheric plasma spraying. The coatings were deposited onto stainless-steel meshes forming a highly porous network mainly composed of nanostructured Ni and highly active Ni4Mo. High material loading (200 mg cm-2) with large surface area (1769 cm2 per cm2) was achieved without compromising the foam-like characteristics. The coatings exhibited excellent activity towards both hydrogen evolution (HER) and oxygen evolution (OER) reactions in alkaline media. The HER active coating required an overpotential of 42 mV to reach a current density of -50 mA cm-2 with minimum degradation after a 24 h chronoamperometry test at -10 mA cm-2. Theoretical simulations showed that several crystal surfaces of Ni4Mo exhibit near optimum hydrogen adsorption energies and improved water dissociation that benefit the HER activity. The OER active coating also consisting of nanostructured Ni and Ni4Mo required only 310 mV to achieve a current density of 50 mA cm-2. The OER activity was maintained even after 48 h of continuous operation. We envisage that the development of scalable production techniques for Ni4Mo alloys will greatly benefit its usage in commercial alkaline water electrolysers.

New insights into the hydrogen evolution reaction using Ni-ZIF8/67-derived electrocatalysts

One of the present great challenges is finding nonprecious materials characterized by efficient electrocatalytic behavior in order to substitute the expensive platinum-based materials for the purpose of hydrogen evolution reactions (HERs). In this study, ZIF-67 and ZIF-67 were used as precursors in order to fabricate metallic-doped N-enriched carbon successfully through a simple process of pyrolysis for applying the hydrogen evolution reaction. In addition, nickel was added to these structures in the course of the synthesis procedure. While under high-temperature treatment, Nickel doped ZIF-67 was transformed into metallic NiCo doped N enriched carbon (NiCo/NC), under high-temperature treatments, Ni-doped ZIF-8 changed into metallic NiZn doped N enriched carbon (NiZn/NC). By combining metallic precursors, the following five structures were synthesized: NiCo/NC, Co/NC, NiZn/NC, NiCoZn/NC, as well as CoZn/NC. It is noteworthy that the produced Co/NC shows optimum hydrogen evolution reaction activity along with superior overpotential of 97 mV and the minimum Tafel slope of 60 mV/dec at 10 mA cm. In addition, the superb behavior of hydrogen evolution reaction can be attributable to the numerous active sites, the superior electrical conductivity of carbon, and the firm structure. As a result, the present paper suggests a novel strategy in order to produce nonprecious materials characterized by superb HER efficiency for future scholars.

Progress in electrocatalytic hydrogen evolution of transition metal alloys: synthesis, structure, and mechanism analysis

At present, the problems of high energy consumption and low efficiency in electrocatalytic hydrogen production have limited the large-scale industrial application of this technology. Constructing effective catalysts has become the way to solve these problems. Transition metal alloys have been proved to be very promising materials in hydrogen evaluation reaction (HER). In this study, the related theories and characterization methods of electrocatalysis are summarized, and the latest progress in the application of binary, ternary, and high entropy alloys to HER in recent years is analyzed and studied. The synthesis methods and optimization strategies of transition metal alloys, including composition regulation, hybrid engineering, phase engineering, and morphological engineering were emphatically discussed, and the principles and performance mechanism analysis of these strategies were discussed in detail. Although great progress has been made in alloy catalysts, there is still considerable room for applications. Finally, the challenges, prospects, and research directions of transition metal alloys in the future were predicted.

Inverse 'intra-lattice' charge transfer in nickel-molybdenum dual electrocatalysts regulated by under-coordinating the molybdenum center

The prevalence of intermetallic charge transfer is a marvel for fine-tuning the electronic structure of active centers in electrocatalysts. Although Pauling electronegativity is the primary deciding factor for the direction of charge transfer, we report an unorthodox intra-lattice 'inverse' charge transfer from Mo to Ni in two systems, Ni₇₃Mo alloy electrodeposited on Cu nanowires and NiMo-hydroxide (Ni : Mo = 5 : 1) on Ni foam. The inverse charge transfer deciphered by X-ray absorption fine structure studies and X-ray photoelectron spectroscopy has been understood by the Bader charge and projected density of state analyses. The undercoordinated Mo-center pushes the Mo 4d-orbitals close to the Fermi energy in the valence band region while Ni 3d-orbitals lie in the conduction band. Since electrons are donated from the electron-rich Mo-center to the electron-poor Ni-center, the inverse charge transfer effect navigates the Mo-center to become positively charged and vice versa. The reverse charge distribution in Ni₇₃Mo accelerates the electrochemical hydrogen evolution reaction in alkaline and acidic media with 0.35 and 0.07 s^-1 turnover frequency at -33 ± 10 and -54 ± 8 mV versus the reversible hydrogen electrode, respectively. The corresponding mass activities are 10.5 ± 2 and 2.9 ± 0.3 A g^-1 at 100, and 54 mV overpotential, respectively. Anodic potential oxidizes the Ni-center of NiMo-hydroxide for alkaline water oxidation with 0.43 O₂ s^-1 turnover frequency at 290 mV overpotential. This extremely durable homologous couple achieves water and urea splitting with cell voltages of 1.48 ± 0.02 and 1.32 ± 0.02 V, respectively, at 10 mA cm^-2.

Underfocus Laser Induced Ni Nanoparticles Embedded Metallic MoN Microrods as Patterned Electrode for Efficient Overall Water Splitting

Transition metal nitrides have shown large potential in industrial application for realization of the high active and large current density toward overall water splitting, a strategy to synthesize an inexpensive electrocatalyst consisting of Ni nanoparticles embedded metallic MoN microrods cultured on roughened nickel sheet (Ni/MoN/rNS) through underfocus laser heating on NiMoO₄ ·xH₂ O under NH₃ atmosphere is posited. The proposed laser preparation mechanism of infocus and underfocus modes confirms that the laser induced stress and local high temperature controllably and rapidly prepared the patterned Ni/MoN/rNS electrodes in large size. The designed Ni/MoN/rNS presents outstanding catalytic performance for hydrogen evolution reaction (HER) with a low overpotential of 67 mV to deliver a current density of 10 mA cm^-2 and for the oxygen evolution reaction (OER) with a small overpotential of 533 mV to deliver 200 mA cm^-2 . Density functional theory (DFT) calculations and Kelvin probe force microscopy (KPFM) further verify that the constructed interface of Ni/MoN with small hydrogen absorption Gibbs free energy (ΔG_H* ) (-0.19 eV) and similar electrical conductivity between Ni and metallic MoN, which can explain the high intrinsic catalytic activity of Ni/MoN. Further, the constructed two-electrode system (-) Ni/MoN/rNS||Ni/MoN/rNS (+) is employed in an industrial water-splitting electrolyzer (460 mA cm^-2 for 120 h), being superior to the performance of commercial nickel electrode.

Metal-Organic Framework-Derived Hollow CoSx Nanoarray Coupled with NiFe Layered Double Hydroxides as Efficient Bifunctional Electrocatalyst for Overall Water Splitting

For effective hydrogen production by water splitting, it is essential to develop earth-abundant, highly efficient, and durable electrocatalysts. Herein, the authors report a bifunctional electrocatalyst composed of hollow CoS_x and Ni-Fe based layered double hydroxide (NiFe LDH) nanosheets for efficient overall water splitting (OWS). The optimized heterostructure is obtained by the electrodeposition of NiFe LDH nanosheets on metal-organic framework-derived hollow CoS_x nanoarrays, which are supported on nickel foam (H-CoS_x @NiFe LDH/NF). The unique structure of the hybrid material not only provides ample active sites, but also facilitates electrolyte penetration and gas release during the reactions. Additionally, the strong coupling and synergy between the hydrogen evolution reaction (HER) active CoS_x and the oxygen evolution reaction (OER) active NiFe LDH gives rise to the excellent bifunctional properties. Consequently, H-CoS_x @NiFe LDH/NF exhibits remarkable HER and OER activities with overpotentials of 95 and 250 mV, respectively at 10 mA cm^-2 in 1.0 M KOH. Even at 1.0 A cm^-2 , the electrode requires small overpotentials of 375 mV (for HER) and 418 mV (for OER), respectively. An electrolyzer based on H-CoS_x @NiFe LDH/NF demonstrates a low cell voltage of 1.98 V at a current density of 300 mA cm^-2 and good durability for 100 h in OWS application.

Nickel-Based Electrocatalysts for Water Electrolysis

Currently, hydrogen production is based on the reforming process, leading to the emission of pollutants; therefore, a substitute production method is imminently required. Water electrolysis is an ideal alternative for large-scale hydrogen production, as it does not produce any carbon-based pollutant byproducts. The production of green hydrogen from water electrolysis using intermittent sources (e.g., solar and eolic sources) would facilitate clean energy storage. However, the electrocatalysts currently required for water electrolysis are noble metals, making this potential option expensive and inaccessible for industrial applications. Therefore, there is a need to develop electrocatalysts based on earth-abundant and low-cost metals. Nickel-based electrocatalysts are a fitting alternative because they are economically accessible. Extensive research has focused on developing nickel-based electrocatalysts for hydrogen and oxygen evolution. Theoretical and experimental work have addressed the elucidation of these electrochemical processes and the role of heteroatoms, structure, and morphology. Even though some works tend to be contradictory, they have lit up the path for the development of efficient nickel-based electrocatalysts. For these reasons, a review of recent progress is presented herein.

Three-Dimensional Hierarchical Core/shell Electrodes Using Highly Conformal TiO2 and Co3O4 Thin Films for High-Performance Supercapattery Devices

The rational design and development of novel electrode materials with promising nanostructures is an effective technique to improve their supercapacitive performance. This work presents high-performance core/shell electrodes based on three-dimensional hierarchical nanostructures coated with conformal thin transition-metal oxide layers using atomic layer deposition (ALD). This effective interface engineering creates disorder in the electronic structure and coordination environment at the interface of the heteronanostructure, which provides many more reaction sites and rapid ion diffusion. At 3 A g^-1, the positive CuCo₂O₄/Ni₄Mo/MoO₂@ALD-Co₃O₄ electrode introduced here exhibits a specific capacity of 1029.1 C g^-1, and the fabricated negative Fe₃O₄@ALD-TiO₂ electrode significantly outperforms conventional carbon-based electrodes, with a maximum specific capacity of 372.6 C g^-1. The supercapattery cell assembled from these two interface- and surface-tailored electrodes exhibits a very high energy density of 110.4 W h kg^-1 with exceptional capacity retention over 20,000 cycles, demonstrating the immense potential of ALD for the next generation of supercapacitors.

3D Printed Nickel-Molybdenum-Based Electrocatalysts for Hydrogen Evolution at Low Overpotentials in a Flow-Through Configuration

Three-dimensional (3D) printed, hierarchically porous nickel molybdenum (NiMo) electrocatalysts were synthesized and evaluated in a flow-through configuration for the hydrogen evolution reaction (HER) in 1.0 M KOH(aq) in a simple electrochemical H-cell. 3D NiMo electrodes possess hierarchically porous structures because of the resol-based aerogel precursor, which generates superporous carbon aerogel as a catalyst support. Relative to a traditional planar electrode configuration, the flow-through configuration allowed efficient removal of the hydrogen bubbles from the catalyst surface, especially at high operating current densities, and significantly decreased the overpotentials required for HER. An analytical model that accounted for the electrokinetics of HER as well as the mass transport with or without the flow-through configuration was developed to quantitatively evaluate voltage losses associated with kinetic overpotentials and ohmic resistance due to bubble formation in the porous electrodes. The chemical composition, electrochemical surface area (ECSA), and roughness factor (RF) were also systematically studied to assess the electrocatalytic performance of the 3D printed, hierarchically porous NiMo electrodes. An ECSA of 25163 cm² was obtained with the highly porous structures, and an average overpotential of 45 mV at 10 mA cm^-2 was achieved over 24 h by using the flow-through configuration. The flow-through configuration evaluated in the simple H-cell achieved high electrochemical accessible surface areas for electrochemical reactions and provided useful information for adaption of the porous electrodes in flow cells.

Coupling Interface Constructions of FeNi3-MoO2 Heterostructures for Efficient Urea Oxidation and Hydrogen Evolution Reaction

Urea electrolysis has prospects for urea-containing wastewater purification and hydrogen (H₂) production, but the shortage of cost-effective catalysts restricts its development. In this work, the tomentum-like FeNi₃-MoO₂ heterojunction nanosheets array self-supported on nickel foam (NF) as bifunctional catalyst is prepared by facile hydrothermal and annealing method. Only 1.29 V and -50.8 mV is required to obtain ±10 mA cm^-2 for urea oxidation and hydrogen evolution reaction (UOR and HER), respectively, showing great bifunctional catalytic activity. For overall urea electrolysis, it only needs 1.37 V to reach 10 mA cm^-2 and can last at 100 mA cm^-2 for 70 h without obvious activity attenuation, showing outstanding durability. Coupling interface constructions of FeNi₃-MoO₂ heterostructures, novel morphology with a mesoporous and self-supporting structure could be the reason for this good performance. This work thus proposes a promising catalyst for boosting UOR and HER to realize efficient overall urea electrolysis.

Hollow nanosphere arrays with a high-index contrast for enhanced scintillating light output from β-Ga2O3 crystals

β-Ga₂O₃ is a new type of fast scintillator with potential applications in medical imaging and nuclear radiation detection with high count-rate situations. Because of the severe total internal reflection with its high refractive index, the light extraction efficiency of β-Ga₂O₃ crystals is rather low, which would limit the performance of detection systems. In this paper, we use hollow nanosphere arrays with a high-index contrast to enhance the light extraction efficiency of β-Ga₂O₃ crystals. We can increase the transmission diffraction efficiency and reduce the reflection diffraction efficiency through controlling the refractive index and the thickness of the shell of the hollow nanospheres, which can lead to a significant increase in the light extraction efficiency. The relationships between the light extraction efficiency and the refractive index and thickness of the shell of the hollow nanospheres are investigated by both numerical simulations and experiments. It is found that when the refractive index of the shell of the hollow nanospheres is higher than that of β-Ga₂O₃, the light extraction efficiency is mainly determined by the diffraction efficiency of light transmitted from the surface with the hollow nanosphere arrays. When the refractive index of the shell is less than that of β-Ga₂O₃, the light extraction efficiency is determined by the ratio of the diffraction efficiency of the light transmitted from the surface with the hollow nanosphere arrays to the diffraction efficiency of the light that can escape from the lateral surface.

Interfacial Engineering of a MoO2-CeF3 Heterostructure as a High-Performance Hydrogen Evolution Reaction Catalyst in Both Alkaline and Acidic Solutions

Exploring an efficient and pollution-free hydrogen evolution reaction (HER) electrocatalyst based on the combination of rare-earth metal and nonnoble metal is of significant importance. However, successfully achieving such a goal remains highly challenging. Herein, a nanosheet comprising a MoO₂-CeF₃ heterojunction (MoO₂-CeF₃/NF) is successfully prepared via a three-step method. (1) Growth of hexahedral nickel hydroxide [Ni(OH)₂] on a 3D nickel foam (NF) as the scaffold. (2) In situ hydrothermal growth of a precursor nanosheet structure on the scaffold. (3) Calcination treatment at 450 °C in the presence of hydrogen. Herein, the electron redistribution at the heterointerface of CeF₃ and MoO₂ is a contributing factor toward enhanced HER activity. Appropriate introduction of CeF₃ can enlarge the size of nanosheets, increase numerous active sites, increase the catalytic durability of the material, and change electron distribution on the MoO₂ interface; all of the above improve HER activity. Because of its interfacial nanosheet structure, MoO₂-CeF₃/NF demonstrates pre-eminent HER capability in both alkaline (1.0 M KOH) and acidic (0.5 M H₂SO₄) electrolytes, with extremely small overpotentials of 18 and 42 mV at 10 mA cm^-2, respectively. This is obviously lower than the overpotential of Pt/C in alkaline media (27 mV), and it is also close to the overpotential of Pt/C in acidic media (41 mV), at the same current density_. More importantly, MoO₂-CeF₃/NF displays a better HER activity than Pt/C at a current density of >112 mA cm^-2 in both alkaline and acidic electrolytes. This work offers a novel strategy toward high-performance hydrogen production by designing a transition metal oxide and rare-earth metal heterojunction.

Multi-dimensional collaboration promotes the catalytic performance of 1D MoO3 nanorods decorated with 2D NiS nanosheets for efficient water splitting

The ability to manipulate heterostructures is of great importance to achieve high-performance electrocatalysts for direct water-splitting devices with excellent activity toward hydrogen production. Herein, a novel top-down strategy involving the in situ transformation of one-dimensional MoO3 nanorod arrays grafted with two-dimensional NiS nanosheets supported on a three-dimensional nickel foam skeleton is proposed. Namely, a heterostructured electrocatalyst on the Ni foam skeleton containing MoO3 nanorod arrays decorated with NiS nanosheets is synthesized by a facile hydrothermal method followed by one-step sulfidation treatment. Experimental analysis confirmed that this novel composite has the merits of a large quantity of accessible active sites, unique distribution of three different spatial dimensions, accelerated mass/electron transfer, and the synergistic effect of its components, resulting in impressive electrocatalytic properties toward the hydrogen evolution reaction and oxygen evolution reaction. Furthermore, an advanced water-splitting electrolyzer was assembled with NiS/MoO3/NF as both the anodic and cathodic working electrode. This device requires a low cell voltage of 1.56 V to afford a water-splitting current density of 10 mA·cm-2 in basic electrolyte, outperforming previously reported electrocatalysts and even state-of-the-art electrocatalysts. More significantly, this work provides a way to revolutionize the design of heterostructured electrocatalysts for the large-scale commercial production of hydrogen using direct water-splitting devices.

Single-Crystalline Mo-Nanowire-Mediated Directional Growth of High-Index-Faceted MoNi Electrocatalyst for Ultralong-Term Alkaline Hydrogen Evolution

As appealing alternatives to noble-metal-based electrocatalysts for catalyzing hydrogen evolution reaction (HER) in alkali electrolyzers, earth-abundant MoNi-based catalysts have attracted intensive attention. Unfortunately, the exploration of MoNi-based electrocatalysts with superior intrinsic activity and ultralong-term stability still remains a grand challenge. Here, ultralong high-index faceted Mo@MoNi core-shell nanowires were topochemically synthesized through the thermal reduction of Mo@NiMoO₄ core-shell nanowires, where single-crystalline Mo support facilitates the topological transformation of NiMoO₄ into high-index faceted MoNi. When the as-achieved Mo@MoNi core-shell nanowire film serve as a free-standing cathode in alkaline solutions, it exhibit a remarkably decreased HER overpotential of 18 mV at 10 mA cm^-2 and a Tafel slope of ∼33 mV dec^-1, which are much lower than those for the state-of-the-art earth-abundant electrocatalysts and even commercial Pt/C. Experimental and theoretical investigations reveal that the exposed high-index (331) facets of MoNi can considerably reduce the energy barriers of initial water dissociation and subsequent hydrogen combination steps, which synergistically accelerates the sluggish alkaline HER kinetics. Significantly, after a 70-day HER operation, the overpotential of Mo@MoNi electrocatalysts at 10 mA cm^-2 decreases by only 4 mV. Therefore, this work sheds a bright light on the rational design of high-performance HER electrocatalysts and their practical utilization for alkaline electrolyzers.

A novel MoNi@Ni(OH)2 heterostructure with Pt-like and stable electrocatalytic activity for the hydrogen evolution reaction

A novel Mo0.84Ni0.16@Ni(OH)2 heterostructure was successfully fabricated. Owing to the unique interface structure and strong synergistic effects between different components, the heterostructure shows enhanced activity for the hydrogen evolution reaction (HER), outperforming that of the state-of-the-art Pt/C catalyst.

Sulfur vacancy-tailored NiCo2S4 nanosheet arrays for the hydrogen evolution reaction at all pH values

Sulfur vacancy-tailored NiCo₂S₄ nanosheet arrays as efficient electrocatalysts for the hydrogen evolution reaction at all pH values.