Ultrafine IrMnOx Nanocluster Decorated Amorphous PdS Nanowires as Efficient Electrocatalysts for High C1 Selectivity in the Alkaline Ethanol Oxidation Reaction.

As a novel electrochemical energy conversion device, direct ethanol fuel cells are currently encountering two significant challenges: CO poisoning and the difficulty of C-C bond cleavage in ethanol. In this work, an amorphous PdS nanowires/ultrafine IrMnOx bimetallic oxides (denoted as a-PdS/IrMnOx NWs) catalyst with abundant oxide/metal (crystalline/amorphous) inverse heterogeneous interfaces was synthesized via a hydrothermal process succeeded by a nonthermal air-plasma treatment. This unique interfacial electronic structure along with the incorporation of oxyphilic metal has resulted in a significant enhancement in the electrocatalytic performance of a-PdS/IrMnOx NWs toward the ethanol oxidation reaction, achieving current densities of 12.45 mA·cm-2 and 3.68 A·mgPd-1. Moreover, the C1 pathway selectivity for ethanol oxidation has been elevated to 47%, exceeding that of other as-prepared Pd-based counterparts and commercial Pd/C catalysts. Density functional theory calculations have validated the findings that the decoration of IrMn species onto the amorphous PdS surface has induced a charge redistribution in the interface region. The redistribution of surface charges on the a-PdS/IrMnOx NWs catalyst results in a significant decrease in the activation energy required for C-C bond cleavage and a notable weakening of the CO binding strength at the Pd active sites. Consequently, it enhanced both the EOR C1 pathway selectivity and CO poisoning resistance to the a-PdS/IrMnOx NWs catalyst.

Correlating the crystal structure and facet of indium oxides with their activities for CO2 electroreduction.

Constructing structure-function relationships is critical for the rational design and development of efficient catalysts for CO2 electroreduction reaction (CO2RR). In2O3 is well-known for its specific ability to produce formic acid. However, how the crystal phase and surface affect the CO2RR activity is still unclear, making it difficult to further improve the intrinsic activity and screen for the most active structure. In this work, cubic and hexagonal In2O3 with different stable surfaces ((111) and (110) for cubic, (120) and (104) for hexagonal) are investigated for CO2RR. Theoretical results demonstrate that the adsorption of reactants on cubic In2O3 is stronger than that on hexagonal In2O3, with the cubic (111) surface being the most active for CO2RR. In experiments, synthesized cubic In2O3 nanosheets with predominantly exposed (111) surfaces exhibited a high HCOO- Faradaic efficiency (87.5%) and HCOO- current density (-16.7 mA cm-2) at -0.9 V vs RHE. In addition, an aqueous Zn-CO2 battery based on a cubic In2O3 cathode was assembled. Our work correlates the phases and surfaces with the CO2RR activity, and provides a fundamental understanding of the structure-function relationship of In2O3, thereby contributing to further improvements in its CO2RR activity. Moreover, the results provide a principle for the directional preparation of materials with optimal phases and surfaces for efficient electrocatalysis.

Recent research progresses of Sn/Bi/In-based electrocatalysts for electroreduction CO2 to formate.

Carbon dioxide electroreduction reaction (CO2RR) can take full advantage of sustainable power to reduce the continuously increasing carbon emissions. Recycling CO2 to produce formic acid or formate is a technologically and economically viable route to accomplish CO2 cyclic utilization. Developing efficient and cost-effective electrocatalysts with high selectivity towards formate is prioritized for the industrialized applications of CO2RR electrolysis. From the previous explored CO2RR catalysts, Sn, Bi and In based materials have drawn increasing attentions due to the high selectivity towards formate. However, there are still confronted with several challenges for the practical applications of these materials. Therefore, a rational design of the catalysts for formate is urgently needed for the target of industrialized applications. Herein, we comprehensively summarized the recent development in the advanced electrocatalysts for the CO2RR to formate. Firstly, the reaction mechanism of CO2RR is introduced. Then the preparation and design strategies of the highly active electrocatalysts are presented. Especially the innovative design mechanism in engineering materials for promoting catalytic performance, and the efforts on mechanistic exploration using in situ (ex situ) characterization techniques are reviewed. Subsequently, some perspectives and expectations are proposed about current challenges and future potentials in CO2RR research.

Reconstructed Bismuth Oxide through in situ Carbonation by Carbonate-containing Electrolyte for Highly Active Electrocatalytic CO2 Reduction to Formate.

The catalyst-reconstruction makes it challenging to clarify the practical active sites and unveil the actual reaction mechanism during the CO2 electroreduction reaction (CO2 RR). However, currently the impact of the electrolyte microenvironment in which the electrolyte is in contact with the catalyst is overlooked and might induce a chemical evolution, thus confusing the reconstruction process and mechanism. In this work, the carbonate adsorption properties of metal oxides were investigated, and the mechanism of how the electrolyte carbonate affect the chemical evolution of catalysts were discussed. Notably, Bi2 O3 with weak carbonate adsorption underwent a chemical reconstruction to form the Bi2 O2 CO3 /Bi2 O3 heterostructure. Furthermore, in situ and ex situ characterizations unveiled the formation mechanism of the heterostructure. The in situ formed Bi2 O2 CO3 /Bi2 O3 heterostructure with strong electron interaction served as the highly active structure for CO2 RR, achieving a formate Faradaic efficiency of 98.1 % at -0.8 Vvs RHE . Theoretical calculations demonstrate that the significantly tuned p-orbit electrons of the Bi sites in Bi2 O2 CO3 /Bi2 O3 optimized the adsorption of the intermediate and lowered the energy barrier for the formation of *OCHO. This work elucidates the mechanism of electrolyte microenvironment for affecting catalyst reconstruction, which contributes to the understanding of reconstruction process and clarification of the actual catalytic structure.

High-Entropy Layered Double Hydroxides with Highly Adjustable Components for Enhancing Electrocatalytic Oxygen Evolution.

The main obstacle to the development of large-scale electrochemical hydrogen production based on water splitting is the slow four-electron kinetics of OER (oxygen evolution reaction). The most efficient method is to create sophisticated and effective OER catalysts. Here, we proposed the controlled synthesis of high-entropy layered double hydroxides (HELDH) for wide component regulation and the component design of high OER activity to make up for the restricted component regulation in conventional catalysts. Through the use of coprecipitation and hydrothermal synthesis, the representative sample (MgCoNi)3(FeAl)-LDH is created and systematically characterized. Significantly, this technique of preparation may generically synthesize a variety of HELDH with various component combinations, demonstrating the remarkable adaptability of the HELDH components. Subsequently, (FeCoNi)3(FeCr)-LDH with high OER activity is designed and synthesized. (FeCoNi)3(FeCr)-LDH shows excellent OER activity (overpotential is only 230 mV at 10 mA cm-2). A new platform for the creation of high-performance catalysts and high-entropy materials was established by the synthesis and design of HELDH.

Accelerate charge separation in Cu2O/MoO2 photocathode for photoelectrocatalytic hydrogen evolution.

Photoelectrocatalyzing water reduction is a potential approach to building a green and sustainable society. As a benchmark photocathode, Cu2O receives much attention but faces serious charge recombination and photocorrosion. This work prepared an excellent Cu2O/MoO2 photocathode via in situ electrodeposition. A systematical study of theory and experiment demonstrates that MoO2 not only effectively passivates the surface state of Cu2O as well as accelerates reaction kinetics as a cocatalyst, but also promotes the directional migration and separation of photogenerated charge. As expected, the constructed photocathode exhibits a highly enhanced photocurrent density and an appealing energy transformation efficacy. Importantly, MoO2 can inhibit the reduction of Cu+ in Cu2O via a formed internal electric field and shows excellent photoelectrochemical stability. These findings pave the way to designing a high-activity photocathode with high stability.

Designing Breathing Air-electrode and Enhancing the Oxygen Electrocatalysis by Thermoelectric Effect for Efficient Zn-air Batteries.

The sluggish kinetics and mutual interference of oxygen evolution and reduction reactions in the air electrode resulted in large charge/discharge overpotential and low energy efficiency of Zn-air batteries. In this work, we designed a breathing air-electrode configuration in the battery using P-type Ca3 Co4 O9 and N-type CaMnO3 as charge and discharge thermoelectrocatalysts, respectively. The Seebeck voltages generated from thermoelectric effect of Ca3 Co4 O9 and CaMnO3 synergistically compensated the charge and discharge overpotentials. The carrier migration and accumulation on the cold surface of Ca3 Co4 O9 and CaMnO3 optimized the electronic structure of metallic sites and thus enhanced their intrinsic catalytic activity. The oxygen evolution and reduction overpotentials were enhanced by 101 and 90 mV, respectively, at temperature gradient of 200 °C. The breathing Zn-air battery displayed a remarkable energy efficiency of 68.1 %. This work provides an efficient avenue towards utilizing waste heat for improving the energy efficiency of Zn-air battery.

Lattice oxygen activation in disordered rocksalts for boosting oxygen evolution.

The recent development of some special oxygen evolution reaction (OER) electrocatalysts shows that the lattice oxygen could participate in the catalysis process via the lattice oxygen oxidation mechanism (LOM), which the provides good possibility of exploring advanced electrocatalysts that could overcome the scaling relationship in conventional catalysis processes through a traditional adsorbate evolution mechanism. In this work, we theoretically predict that, benefiting from the unhybridized O-Li orbitals and the resulting metastable Li-O-Li ligands, the lattice oxygen could be easily activated and oxidized at relatively high oxidation voltages. Thus, lithium-excess disordered rocksalts (DRX) should possess the potential for acting as active OER electrocatalysts, which catalyze through the LOM pathway. The isotope labelling experimental results show that the lattice oxygen in the DRX was activated and participated in the OER process through the LOM pathway. The typical DRX of Li1.2Fe0.4Ti0.5O2 displays obviously pH-dependent OER activity under the LOM process and shows a low overpotential of 263 mV to reach 10 mA cm-2 with long-term stability for 100 hours. The turnover frequency of Li1.2Fe0.4Ti0.5O2 is nearly 9 times that of LiFePO4 at the overpotential of 300 mV. This work opens a new chemical space for exploring efficient electrocatalysts to enhance the OER performance through the LOM pathway.

Activating RuOCo Interaction on the a-Co(OH)2 @Ru Interface for Accelerating the Volmer Step of Alkaline Hydrogen Evolution.

The state-of-the-art active hydrogen evolution reaction (HER) catalysts in acid electrolytes generally lose considerable catalytic performance in alkaline electrolytes mainly due to the additional water dissociation step. Designing composite materials is an effective strategy to accelerate alkaline water electrolysis by optimizing the electronic structure of materials. Here, different phases of Co(OH)2 -supported Ru clusters (α/ß-Co(OH)2 @Ru) are prepared for enabling a highly efficient electrocatalytic HER performance in alkaline solution. The prepared α-Co(OH)2 nanosheets facilitate the loading of uniform and high-density Ru clusters and the formed highly active RuOCo bonds at the interface. The synergistic interaction endows the hybrid catalyst with low overpotential of 33 mV at 10 mA cm-2 . Moreover, the homemade anion exchange membrane water electrolysis cell based on α-Co(OH)2 @Ru affords a cell voltage of 2 V to drive a current density of 270 mA cm-2 and performs stably during continuous operation for over 100 h. Density functional theory calculations demonstrate that active RuOCo bonds in α-Co(OH)2 @Ru optimize the energy barriers for H2 O dissociation and OH- desorption to facilitate the Volmer reaction step. This work offers a strategy for designing interfacial chemical bonds for high electrocatalytic activity.

Structural Framework-Guided Universal Design of High-Entropy Compounds for Efficient Energy Catalysis.

High-entropy compounds with extraordinary properties due to the synergistic effect of multiple components have exhibited great potential and attracted extensive attention in various fields, including physics, mechanical property analysis, and energy storage. Achieving universal stability and synthesis of high-entropy compounds with a wide range of components and structures continues to be difficult due to the high complexity of multicomponent mixing. Here, we propose a design strategy with high generality for realizing the stability and synthesis of high-entropy compounds that one metal site like the framework in the compound structures with bimetallic sites stabilizes another site to accommodate different elements. Several typical metal compounds with bimetallic sites, including perovskite hydroxides, layered double hydroxide, spinel sulfide, perovskite fluoride, and spinel oxides, have been synthesized into high-entropy compounds. High-entropy perovskite hydroxides (HEPHs) as representative compounds have been synthesized with a highly wide range of components even a septenary component and exhibit great oxygen evolution activity. Our work provides a design platform to develop more high-entropy compound systems with promising development potential for electrocatalysts.

Amorphous Mo-doped NiS0.5 Se0.5 Nanosheets@Crystalline NiS0.5 Se0.5 Nanorods for High Current-density Electrocatalytic Water Splitting in Neutral Media.

It is vitally important to develop highly active, robust and low-cost transition metal-based electrocatalysts for overall water splitting in neutral solution especially at large current density. In this work, amorphous Mo-doped NiS0.5 Se0.5 nanosheets@crystalline NiS0.5 Se0.5 nanorods (Am-Mo-NiS0.5 Se0.5 ) was synthesized using a facil one-step strategy. In phosphate buffer saline solution, the Am-Mo-NiS0.5 Se0.5 shows tiny overpotentials of 48 and 209 mV for hydrogen evolution reaction (HER), 238 and 514 mV for oxygen evolution reaction (OER) at 10 and 1000 mA cm-2 , respectively. Moreover, Am-Mo-NiS0.5 Se0.5 delivers excellent stability for at least 300 h without obvious degradation. Theoretical calculations revealed that the Ni sites in the defect-rich amorphous structure of Am-Mo-NiS0.5 Se0.5 owns higher electron state density and strengthened the binding energy of H2 O, which will optimize H adsorption/desorption energy barriers and reduce the adsorption energy of OER determining step.

Poly(acrylic acid)-Based Composite Gel Polymer Electrolytes with High Mechanical Strength and Ionic Conductivity toward Flexible Zinc-Air Batteries with Long Cycling Lifetime.

The rapid development of portable, flexible, and wearable devices motivates the requirement for flexible zinc-air batteries (FZABs) not only to provide high energy density but also to have sufficient deformability for wearer comfort. The gel polymer electrolyte (GPE) serves as the core part of the FZABs, playing a key function in the battery's practical output performance such as discharge voltage, energy density, and cycling life. Unfortunately, ascribed to its high water absorption, the GPE regularly shows comparatively poor mechanical strength, which is difficult to offer sufficient physical support between electrodes. Herein, we report an optimized poly(acrylic acid) (PAA)-based composite GPE with the aluminum oxide (Al2O3) filler and apply it for FZAB. The mechanical strength, electrolyte absorption capacity, electrolyte retention ability, and ionic conductivity of the PAA-Al2O3 gel polymers and corresponding GPEs were investigated. The results indicate that the above performances of polymers and corresponding GPEs depend to a considerable extent on the content of the addition of Al2O3 particles. When 20 wt.% Al2O3 is added to the PAA polymer, the obtained PAA-20 wt.% Al2O3 gel polymer exhibits improved mechanical strength. The corresponding PAA-20 wt.% Al2O3 GPE shows a high ionic conductivity of 186 mS cm-1 and pleasurable electrolyte retention capability. This optimized GPE enables the assembled FZAB to display a long cycling lifetime of 384 h, a large power density of 77.7 mW cm-2, and excellent discharge performance. Moreover, the integrated FZAB can power various electronic devices, demonstrating its outstanding practicability and extensibility as a flexible power source.

Opportunities of Flexible and Portable Electrochemical Devices for Energy Storage: Expanding the Spotlight onto Semi-solid/Solid Electrolytes.

The ever-increasing demand for flexible and portable electronics has stimulated research and development in building advanced electrochemical energy devices which are lightweight, ultrathin, small in size, bendable, foldable, knittable, wearable, and/or stretchable. In such flexible and portable devices, semi-solid/solid electrolytes besides anodes and cathodes are the necessary components determining the energy/power performances. By serving as the ion transport channels, such semi-solid/solid electrolytes may be beneficial to resolving the issues of leakage, electrode corrosion, and metal electrode dendrite growth. In this paper, the fundamentals of semi-solid/solid electrolytes (e.g., chemical composition, ionic conductivity, electrochemical window, mechanical strength, thermal stability, and other attractive features), the electrode-electrolyte interfacial properties, and their relationships with the performance of various energy devices (e.g., supercapacitors, secondary ion batteries, metal-sulfur batteries, and metal-air batteries) are comprehensively reviewed in terms of materials synthesis and/or characterization, functional mechanisms, and device assembling for performance validation. The most recent advancements in improving the performance of electrochemical energy devices are summarized with focuses on analyzing the existing technical challenges (e.g., solid electrolyte interphase formation, metal electrode dendrite growth, polysulfide shuttle issue, electrolyte instability in half-open battery structure) and the strategies for overcoming these challenges through modification of semi-solid/solid electrolyte materials. Several possible directions for future research and development are proposed for going beyond existing technological bottlenecks and achieving desirable flexible and portable electrochemical energy devices to fulfill their practical applications. It is expected that this review may provide the readers with a comprehensive cross-technology understanding of the semi-solid/solid electrolytes for facilitating their current and future researches on the flexible and portable electrochemical energy devices.

Zn-Metal-Organic Framework Derived Ordered Mesoporous Carbon-Based Nanostructure for High-Performance and Universal Multivalent Metal Ion Storage.

Metal-organic framework (MOF) derivatives promise great potential in energy storage and conversion because of their excellent tunability in both the active metal sites, organic links, and the overall structures down to atomic and up to mesoscale. Nevertheless, a big challenge is to precisely control and thoroughly understand the actual MOF-to-derivative conversion process to realize the template-free synthesis of the MOF-derived ordered mesoporous materials. Here, a class of ordered mesoporous N-doped carbon nanoflakes is presented with slit-shaped pores synthesized by one-step pyrolysis of Zn1 Cux -MOF, where the Cu doping plays a critically important direction-inducing function on the dissociation of organic ligands during the pyrolysis. Benefiting from the uniquely ordered mesoporous structure and large specific surface area (910 m2 g-1 ), the Zn1 Cux -MOF-derived ordered mesoporous carbon nanoflakes present outstanding electrochemical storage performance for multivalent metal ions, such as Mg2+ , Ca2+ , Co2+ , Ni2+ , Al3+ , and Zn2+ , demonstrating the universal nature of the slit-shaped pores in enabling the multivalent metal ions for energy storage. Moreover, the assembled flexible Zn-ion hybrid supercapacitor (ZHSC) delivers a high specific capacity of 134 mAh g-1 at 0.5 A g-1 , excellent cycling and mechanical stability, showing great application potential in the new generation energy storage devices.

Mechanistic Insight into Hydrocarbon Synthesis via CO2 Hydrogenation on χ-Fe5C2 Catalysts.

Converting CO2 into value-added chemicals and fuels is one of the promising approaches to alleviate CO2 emissions, reduce the dependence on nonrenewable energy resources, and minimize the negative environmental effect of fossil fuels. This work used density functional theory (DFT) calculations combined with microkinetic modeling to provide fundamental insight into the mechanisms of CO2 hydrogenation to hydrocarbons over the iron carbide catalyst, with a focus on understanding the energetically favorable pathways and kinetic controlling factors for selective hydrocarbon production. The crystal orbital Hamiltonian population analysis demonstrated that the transition states associated with O-H bond formation steps within the path are less stable than those of C-H bond formation, accounting for the observed higher barriers in O-H bond formation from DFT. Energetically favorable pathways for CO2 hydrogenation to CH4 and C2H4 products were identified which go through an HCOO intermediate, while the CH* species was found to be the key C1 intermediate over χ-Fe5C2(510). The microkinetic modeling results showed that the relative selectivity to CH4 is higher than C2H4 in CO2 hydrogenation, but the trend is opposite under CO hydrogenation conditions. The major impact on C2 hydrocarbon production is attributed to the high surface coverage of O* from CO2 conversion, which occupies crucial active sites and impedes C-C couplings to C2 species over χ-Fe5C2(510). The coexistence of iron oxide and carbide phases was proposed and the interfacial sites created between the two phases impact CO2 surface chemistry. Adding potassium into the Fe5C2 catalyst accelerates O* removal from the carbide surface, enhances the stability of the iron carbide catalyst, thus, promotes C-C couplings to hydrocarbons.

Rapid Joule-Heating Synthesis for Manufacturing High-Entropy Oxides as Efficient Electrocatalysts.

High-entropy oxide (HEO) including multiple principal elements possesses great potential for various fields such as basic physics, mechanical properties, energy storage, and catalysis. However, the synthesis method of high-entropy compounds through the traditional heating approach is not conducive to the rapid properties screening, and the current elemental combinations of HEO are also highly limited. Herein, we report a rapid synthesis method for HEO through the Joule-heating of nickel foil with dozens of seconds. High-entropy rocksalt oxides (HERSO) with the new elemental combination, high-entropy spinel oxides (HESO), and high-entropy perovskite oxide (HEPO) have been synthesized through the Joule-heating. The synthesized HERSO with new elemental combinations proves to be a great promotion of OER activity due to the synergy of multiple components and the continuous electronic structure experimentally and theoretically. The demonstrated synthesis approach and the new component combination of HERSO provide a broad platform for the development of high-entropy materials and catalysts.

Single atoms (Pt, Ir and Rh) anchored on activated NiCo LDH for alkaline hydrogen evolution reaction.

Here, we report the synthesis of activated NiCo LDH to immobilize Pt, Ir and Rh single atoms for hydrogen evolution reaction. The Pt/A-NiCo LDH electrocatalyst exhibits the highest catalytic ability with a low overpotential of 16 mV to achieve a current density of 10 mA cm-2 and a mass activity about 24.8-fold that of commercial Pt/C. The results suggest that the Pt single atom catalyst can not only accelerate the Volmer steps in alkaline media, but also optimize the hydrogen adsorption process, improving the HER catalytic activity.

Development and Challenges of Biphasic Membrane-Less Redox Batteries.

Ion exchange membranes (IEMs) play important roles in energy generation and storage field, such as fuel cell, flow battery, however, a major barrier in the way of large-scale application is the high cost of membranes (e.g., Nafion membranes price generally exceeds USD$ 200 m-2 ). The membrane-less technology is one of the promising approaches to solve the problem and thus has attracted much attention and been explored in a variety of research paths. This review introduces one of the representative membrane-less battery types, Biphasic membrane-less redox batteries that eliminate the IEMs according to the principle of solvent immiscibility and realizes the phase splitting in a thermodynamically stable state. It is systematically classified and summarizes their performances as well as the problems they are suffering from, and then several effective solutions are proposed based on the modification of electrodes and electrolytes. Finally, special attention is given to the challenges and prospects of Biphasic membrane-less redox batteries, which could contribute to the development of membrane-less batteries.

Ni-Doped Mo2C Anchored on Graphitized Porous Carbon for Boosting Electrocatalytic N2 Reduction.

Facilitating the efficient activation of N2 molecules and inhibiting the competing hydrogen evolution reaction remain a challenge in the nitrogen reduction reaction (NRR). A heteroatom doping strategy is an effective way to optimize the energy barrier during the NRR process to improve the catalytic efficiency. Herein, we report Ni-doped Mo2C anchored on graphitized porous conductive carbon for regulating the electronic structure and catalytic properties of electrocatalysts toward NRR. Benefiting from the porous structure and graphitization features of the carbon matrix, more active sites and high electronic conductivity were achieved. Meanwhile, with the doping of Ni atoms, the electronic configuration near the Ni-Mo active sites was optimized and the adsorption of N2 on them was also promoted due to the increased electron transfer. Moreover, the lowered energy barrier of the NRR process and the suppressed hydrogen adsorption on the active site all resulted in the high catalytic activity and selectivity of the catalyst. Therefore, a high NH3 yield rate of 46.49 µg h-1 mg-1 and a faradic efficiency of 29.05% were achieved. This work not only validates the important role of heteroatom doping on the regulation of NRR catalytic activity but also provides a promising avenue for the green synthesis of NH3.

Bimetallic Multi-Level Layered Co-NiOOH/Ni3 S2 @NF Nanosheet for Hydrogen Evolution Reaction in Alkaline Medium.

Development of efficient non-noble metal catalysts for water splitting is of great significance but challenging due to the sluggish kinetics of the hydrogen evolution reaction (HER) in alkaline medium. Herein, a bimetallic multi-level layered catalytic electrode composed of Ni3 S2 nanosheets with secondary Co-NiOOH layer of 3D porous and free-standing cathode in alkaline medium is reported. This integrated synergistic catalytic electrode exhibits excellent HER electrocatalytic performance. The resultant Ni0.67 Co0.33 /Ni3 S2 @NF electrode displays the highest HER activity with only overpotentials of 87 and 203 mV to afford current densities of 10 and 100 mA·cm-2 , respectively, and its Tafel slope is 80 mV·dec-1 . The chronopotentiometry operated at high current density of 50 mA·cm-2 shows negligible deterioration, indicating better stability of Ni0.67 Co0.33 /Ni3 S2 @NF electrode than Pt/C (20 wt.%). Such a desirable catalytic performance is attributed to the modification of physical and electronic structure that exposes abundant active sites and improves the intrinsic catalytic activity toward HER, which is also confirmed by electrochemically active surface area and X-ray photoelectron spectroscopy analysis. This work provides a strong support for the rational design of high-performance bimetallic electrodes for industrial water splitting.