HER Performance Research Articles

The tunable double-layer self-supporting Sb-Ni(OH)2 catalyst for boosting electrocatalytic water splitting

Green hydrogen preparation by electrolysis of water is key to driving the energy transition revolution. The development of low-cost, highly active and highly selective catalysts is a top priority for the commercial application from electrolytic water. This paper presents the synthesis of Sb-doped Ni(OH)2 nanosheets growing in situ on Ni foam, which serves as a self-supporting electrode. A straightforward one-step hydrothermal technique was employed to craft a dual-layer catalyst with a tunable morphology. Under the 1 M KOH conditions, Sb-Ni(OH)2-2.5/NF emerged as a bifunctional electrocatalyst, demonstrating an impressive HER performance of 159 mV (η10) and an OER performance of 430.8 mV (η50). The Sb-Ni(OH)2-2.5/NF also demonstrated remarkable stability by 3000 CV cycling tests. The Sb-Ni(OH)2-2.5/NF catalytic material prepared in this paper under laboratory conditions has a simple and inexpensive synthesis method, which helps to move electrolytic water catalysts from the laboratory to industry.

In Situ Growth of MoN on Nickel Foam for Highly Efficient Hydrogen Evolution in Alkaline Solution.

Highly efficient, stable, and low-cost hydrogen evolution catalysts are urgently required for water electrolysis. Herein, a method for in situ growth of medium-nitrogen nanosheet MoN catalysts with a large electrochemical surface area on nickel foam (NF) is proposed. The results show that the morphology of the as-prepared catalysts greatly depends on the nitrogen sources and nitridation temperature. The MoN/NF catalyst nitride at 700 °C using melamine as a nitrogen source exhibits a spindle-like morphology consisting of stacked nanosheets, which is conducive to exposing more active sites, thereby increasing the catalyst activity. The N atoms in MoN could adjust the chemical environment of the metal by changing the density of the d-band electron state, which further improves the HER performance. Benefiting from the regulation of Mo charge distribution and exposure to more active sites through N doping and morphological control, the MoN/NF catalyst exhibits superior HER performance with an overpotential of 70 mV at a current density of 10 mA·cm-2, a Tafel slope of 44.3 mV dec-1, and an Rct of 1.83 Ω, indicating high HER catalytic activity, fast kinetics, and excellent conductivity. Theoretical calculations reveal that among the (002), (202), and (200) planes of MoN, the (202) plane exhibits the lowest value of |ΔGH*| (0.47 eV), which is close to that of Pt(111) (0.14 eV). More importantly, MoN(202) also has the smallest work function of 3.58 eV, indicating an enhanced capability to offer electrons. This work develops a strategy to design high-performance and low-cost transition-metal nitride HER catalysts.

Tin-doped titanium dioxide film-enhanced electrocatalytic hydrogen evolution

Electrocatalyst water-splitting based on metal oxide nanocomposites has gained considerable interest in hydrogen evolution applications. Here, undoped titanium dioxide and tin-doped titanium dioxide films (TiO2 and Sn/TiO2, respectively) are presented for highly efficient H2 production applications. The crystal structure analysis is performed by analyzing the XRD patterns using the Rietveld refinement method and the Williamson-Hall method. XRF scans are used to confirm the doping mechanism between Sn and TiO2. The bandgap energies of undoped TiO2 and Sn/TiO2 films are 3.33 and 3.15 eV, respectively. On the other hand, the electrical conductivity values of undoped TiO2 and Sn/TiO2 films are 0.10 and 0.25 mS.cm−1, respectively. The electrochemical H2 production performance of undoped TiO2 and Sn/TiO2 films is investigated through two different methods: potentiostat measurements and analytical methods. It can be concluded that the Sn/TiO2 film exhibits higher HER performance and H2 production efficiency than the undoped TiO2 film.

Rapid and eco-friendly ultrasonic exfoliation of transition metal dichalcogenides supported on sonogel-nanocarbon black: A non-precious electrocatalyst for hydrogen evolution reaction

Recently, there has been growing interest in replacing expensive platinum-based catalysts with cost-effective non-precious metal alternatives for water electrolysis aimed at hydrogen production. This study introduces an innovative, green, and cost-effective strategy for the development of non-precious electrocatalysts by leveraging sodium alginate-mediated ultrasonic exfoliation to produce transition metal dichalcogenide (TMD) nanosheets. These nanosheets are supported on Sonogel-Carbon electrodes (SGC), providing a novel conductive base for HER catalysis. Using a diverse array of TMD materials, including MoS2, MoSe2, WS2, and WSe2, we assess their catalytic activity towards HER. The study demonstrates significantly enhanced HER performance through bulk modification of the electrodes with nanocarbon black (SGC-CB). This enhancement is primarily due to the synergistic effects of improved electron transfer and increased active site availability, facilitated by the unique structural properties of the exfoliated TMD nanosheets and the conductive Sonogel-Carbon substrate. Notably, the optimized MoSe2NS-SGC-CB configuration achieves an exceptional overpotential of 240 mV at a current density of 10 mA/cm2, surpassing conventional bulk catalysts and highlighting the potential of sodium alginate as a viable dispersing agent for the large-scale production of TMD nanosheets. The operational stability and cost-effectiveness of this electrocatalyst, combined with its environmental friendliness, mark a significant step forward in the pursuit of sustainable hydrogen fuel production technologies.

The impact of graphene on the electrochemical performance of BiMeVOx catalysts in water splitting

The development of efficient catalysts for electrochemical water splitting has become a significant contemporary challenge. Transition metal oxides, due to their unique electrochemical properties, have emerged as promising candidates. Among these, a group of BiMeVOx-based compounds shows particular potential for practical applications in hydrogen and oxygen evolution reactions. However, improvement is still necessary to achieve stable operation of these catalysts in green hydrogen generation. With this is mind, in this study we synthesize BiMeVOx materials with graphene addition using a simple annealing in a tube furnace and investigate their electrochemical properties in HER and OER. After incorporating different metals into the BiMeVOx structure, we observed variations in electrochemical properties; materials with the addition of molybdenum and cobalt (BiMoVOx and BiCoVOx) outperformed materials containing zirconium and cerium (BiZrVOx and BiCeVOx). The BiMoVOx/C catalyst showed excellent HER performance with an overpotential of 432 mV at 10 mA/cm2 and a Tafel slope of 76 mV dec⁻1, while BiCoVOx/C exhibited superior OER activity with a Tafel slope of 100 mV dec⁻1, lower than that of commercial IrO₂. The addition of graphene improved the conductivity and overall activity of the catalysts. These findings indicate that metal doping and graphene incorporation are effective strategies for enhancing the performance of BiMeVOx-based materials in water splitting applications.

I Single-Atom Doped P-Rich CoPn Nanocluster@CoP with Enhanced HER.

Constructing I single-atom (ISA) doped CoP electrocatalyst for HER is extremely challenging and has not been reported to date. Herein, an ISA doping-phosphatization strategy is proposed to prepare a novel I single-atom doped P-rich CoPn nanocluster@CoP electrocatalyst (ISA-CoPn/CoP) with enhanced HER performance first. ISA-CoPn/CoP shows a low overpotential of only 44 and 81mV in 0.5m H2SO4 solution, to drive a current density of 10 and 100mAcm-2. ISA and P-rich CoPn nanocluster show unique synergies, which can optimize the H adsorption energy and accelerate the kinetics of HER in the CoP system. The intermediate I─H bond vibration peak is directly observed through in situ Raman testing, demonstrating that ISA doping helps accelerate the HER process. Additionally, the ΔGH of ISA-CoPn/CoP is only 0.05eV by density functional theory (DFT) calculation, which is conducive to H2 evolution.

Induction heating boosts water splitting on iron-coated nickel foam

Abstract Alkaline water electrolysis at high temperatures can rival acidic proton-exchange membranes.
However, they suffer from increased energy consumption, reduced lifespan of materials and heightened safety risks. Magnetic hyperthermia is a method of localizing intense heating in the presence of an external high-frequency alternating magnetic field. In this study, we developed a custom electromagnetic induction device capable of generating a small magnetic field of about 2 µT. High-permeability nickel foam is used as electrodes. Results show that the iron coated nickel foam decreases the overpotential of the hydrogen evolution reaction and oxygen evolution reaction by ~150 mV and 60 mV, respectively, at 20 mAcm−2 when subjected to magnetic heating in a high-frequency alternating magnetic field. The overall water splitting current of Ni foam/Fe increases 540% under intermittent induction. The enhanced stability of Ni foam/Fe is attributed to the high binding energy of metal-O on the surface. The density function theory calculations further indicates that the lattice expansion of the metal electrode under induction heating optimizes the adsorption and desorption of H*, thereby enhancing the HER performance.

Strong electronic metal-support interaction of Ni4Mo/N-SrMoO4 promotes alkaline hydrogen electrocatalysis

Ni4Mo electrocatalyst stands out as the promising candidate for hydrogen evolution/oxidation reaction (HER/HOR), yet the intensive hydrogen adsorption leads to sluggish kinetics, decreasing hydrogen catalysis efficiency. Herein, the structure of Ni4Mo nanoparticles anchored on wafer-biscuit-like N-SrMoO4 nanorods (Ni4Mo/N-SrMoO4) is developed to accelerate reaction kinetics by modulating electronic structure. The designed N-SrMoO4 support enables strong electronic metal-support interaction with Ni4Mo, resulting in a downward shift of d-band center and achieving thermally neutral hydrogen adsorption. Ni4Mo/N-SrMoO4 exhibits HER performance with an ultralow overpotential of 15 mV at 10 mA cm−2, superior to Pt/C (η10=18 mV). The outstanding exchange current density of 10.2 mA cm−2 for HOR is three times higher than that of Pt/C (3.5 mA cm−2). Ni4Mo/N-SrMoO4 is further assembled in anion exchange membrane water electrolyzer (AEMWE), resulting in a current density of 100 mA cm−2 at voltage of 1.71 V and the excellent stability of 300 hours. Theoretical calculations and in-situ spectroscopy indicate that the introduction of Sr in N-SrMoO4 effectively enhances electronic metal-support interaction, facilitates the enrichment of adsorbed hydroxyl (OHads) on active sites and weakens hydrogen adsorption on Ni4Mo, thereby accelerating reaction kinetics of hydrogen electrocatalysis.

Charge Transfer in n-FeO and p-α-Fe2O3 Nanoparticles for Efficient Hydrogen and Oxygen Evolution Reaction.

This study aims to explore the n-FeO and p-α-Fe2O3 semiconductor nanoparticles in hydrogen (HER) and oxygen (OER) evolution reactions and a combined full cell electrocatalyst system to electrolyze the water. We have observed a distinct electrocatalytic performance for both HER and OER by tuning the interplay between iron oxidation states Fe2+ and Fe3+ and utilizing phase-transformed iron oxide nanoparticles (NPs). The Fe2+ rich n-FeO NPs exhibited superior HER performance compared to p-α-Fe2O3 and Fe(OH)x NPs, which is attributed to the enhancement in n-type semiconducting nature under HER potential, facilitating the electron transfer for the reduction in H+ ions. In contrast, p-α-Fe2O3 NPs demonstrated excellent OER activity. An H-cell constructed using n-FeO||p-α-Fe2O3 NPs as cathode and anode achieved a cell voltage of 1.87 V at a current density of 50 mA/cm2. The cell exhibited remarkable stability after 30 h of activation and maintained the high current density of 100 mA/cm2 for 80 h with a negligible increase in cell voltage. This work highlights the semiconducting properties of n-FeO and p-α-Fe2O3 for the electrochemical water splitting system using the band bending phenomenon under the applied potential.

In situ hydrothermal growth of Ni-based hydrogen phosphate polyhedrons on Ni foam for efficient hydrogen evolution reaction

Developing a cost-effective and stable electrocatalyst is the key to achieve the large-scale applications of water electrolysis to produce green hydrogen. Herein, an in situ hydrothermal growth strategy was put forward to prepare a novel self-supporting electrode, that is, Ni-based hydrogen phosphate polyhedrons supported on 3D Ni foam. This electrode was composed of crystalline (Ni(H2PO4)2·2H2O, Ni(H3P2O7)2·2H2O), and amorphous phase in which NiO nanoparticles formed. The amorphous phase connected polyhedrons to the Ni foam substrate, forming multifarious heterogeneous interfaces. Such a structure possessed large number of active sites, favored the fast reaction kinetics and electron transport rate, synergistically resulting in a superior alkaline HER performance. In alkaline electrolyte, the electrode only needed a small overpotential of 69 mV to reach the current density of 10 mA cm−2 with a small Tafel slope of 56 mV dec−1, and exhibited a good stability at the current density of 100 mA cm−2 for 50 h. This in situ hydrothermal growth strategy opened up a new route to green synthesis of cost-effective and stable 3D heterostructured self-supporting electrode for water-splitting.

Free-standing FeNiCuCoBMo high-entropy alloy bifunctional electrocatalysts for efficient pH-universal water electrolysis

Utilizing the synergistic effects of multi-components has been proven to be a feasible approach to enhance water splitting electrocatalytic activity, since developing efficient and stable bifunctional electrocatalysts within a wide pH range remains a significant challenge. Herein, we report a FeNiCuCoBMo high-entropy alloy (HEA) prepared by dealloying, showing outstanding bifunctional electrocatalytic performance for HER and OER in a pH-universal electrolyte. After dealloying for 7 h, the HER and OER overpotentials of the HEA strips in 1.0 M KOH decreased by 22 mV and 25 mV, respectively.Impressively, the free-standing strips with the optimal compositions achieve low HER (82 mV in acid and 101 mV in alkali at 10 mA·cm−2) and OER (311 mV in acid and 245 mV in alkali at 10 mA·cm−2) overpotentials. In a full hydrolysis experiment, a current of 10 mA·cm−2 can run for 100 h with only 1.58 V, which is attributed to the ample exposure of highly active sites resulting from the synergistic effect of each element. Theoretical calculations further support these findings, showing that the electronegativity differences of the metallic elements in FeNiCuCoBMo result in abnormal activity at specific locations (Fe and Mo).Additionally, charge rearrangement and enhanced electronic conduction at the interface reduce the activation energy barrier, thereby improving the performance of the electrocatalysts.

Boosting hydrogen adsorption via manipulating interfacial electronic structure of NiPx for enhanced alkaline seawater electrolysis

The development of transition metal phosphides (TMPs) electrocatalysts with appropriate binding strength towards intermediates and resistant to chlorine in alkaline seawater electrocatalysis remains a formidable challenge. Herein, an approach for manipulating electron redistribution in Ni2P/Ni5P4 treated by Co cationic doping engineering (denoted as Act-Co-NiPx) is proposed, exhibiting excellent catalytic activities and stability toward HER in alkaline seawater solution. First-principles calculations demonstrate that the Co doping can effectively adjust the electron redistribution of Ni2P/Ni5P4, resulting in a reduction in the hydrogen adsorption free energy for HER and an acceleration in the interfacial charge transfer. Furthermore, the enhanced Cl- adsorption energy avoids the toxicity of Cl- to the active sites in alkaline seawater splitting. Consequently, the resulting Act-Co-NiPx catalyst demonstrates remarkable HER performance with low overpotentials of 77 and 97 mV at a current density of 10 mA cm−2 in both 1.0 M KOH and 1.0 M KOH+Seasalt electrolytes. Furthermore, the seasalt electrolyzer assembled from Act-Co-NiPx achieves the low cell voltage of 1.63 V at 10 mA cm−2. This work demonstrates a feasible method for designing cost-effective and stable catalysts with excellent selectivity via regulating the electronic structure of TMPs for seawater electrolysis.

Comparative electrocatalytic behavior of mesoporous FeP and FeS2 for the hydrogen evolution reaction

FeP nanoparticles and FeS2 nanospheres with mesoporous surface are synthesized, and their performance is compared for the hydrogen evolution reaction under identical electrochemical conditions. The activity-determining characteristics of the electrodes, such as specific and electrochemically active surface area, electrochemical impedance and charge transfer resistance, Tafel slopes, number of catalytic active sites, and turnover frequency (TOF) are studied and correlated to their activity. Because of its larger surface area and reduced charge transfer resistance, the FeS2 showed superior HER performance than the FeP, despite the latter’s higher intrinsic catalytic activity. The electrocatalytic stability of the electrocatalysts are also compared.

Ultrafast Hole Trapping in Te-MoTe2-MoSe2/ZnO S-Scheme Heterojunctions for Photochemical and Photo-/Electrochemical Hydrogen Production.

Te-MoTe2-MoSe2/ZnO S-scheme heterojunctions are engineered to ascertain the advanced redox ability in sustainable HER operations. Photo-physical studies have established the steady state transfer of photo-induced charge carriers whereas an improved transfer dynamics realized by state-of-art ultrafast transient absorption and irradiated-XPS analysis of optimized 5wt% Te-MoTe2-MoSe2/ZnO heterostructure. 2.5, 5, and 7.5wt% Te-MoTe2-MoSe2/ZnO photocatalysts (2.5MTMZ, 5MTMZ and 7.5MTMZ) exhibited 2.8, 3.3, and 3.1-fold higher HER performance than pristine ZnO with marvelous apparent quantum efficiency of 35.09%, 41.42% and 38.79% at HER rate of 4.45, 5.25, and 4.92 mmol/gcat/h, respectively. Electrochemical water splitting experiments manifest subdued 583 and 566 mV overpotential values of 2.5MTMZ and 5MTMZ heterostructures to achieve 10 mAcm-2 current density for HER, and 961 and 793 mV for OER, respectively. For optimized 5MTMZ photocatalyst, lifetime kinetic decay of interfacial charge transfer step is evaluated to be 138.67 ps as compared to 52.92 ps for bare ZnO.

Modulation of π-Electron Density in Ultrathin 2D Layers of Graphite Carbon Nitride for Efficient Photocatalytic Hydrogen Production.

The rational design and synthesis of novel semiconductor nano-/quantum materials have been ambitiously pursued in the field of photocatalysis as the technology is promising and critical for attaining future energy and environmental sustainability. Herein, the integrity of aromatic carbon into graphitic carbon nitride (CN) at the same molecular plane with a few 2D layers is achieved by using modulated precursors of CN, forming carbon regulated ultrathin CN (CUCN) with improved charge transfer kinetics and photocatalytic hydrogen production. The grafted graphite rings adjacent to carbon nitride frameworks induce a significant rearrangement and relocalization of the overall framework, and form conjugated sp2 hybridized interfaces and internal electric fields that drive the separation and directional transfer of photogenerated electrons from CN sheets towards intralayer graphite regions, where the photocatalytic hydrogen evolution reaction occurs extensively, yielding largely increased HER rate of 2231.8 µmol g-1 h-1 by 8.2 times relative to CN, as well as a remarkable apparent quantum yield of 2.93% under monochromatic light at 420 nm. The high physicochemical stability and low synthesis cost of CUCN make it a potential benchmark photocatalyst that can be readily modified via element doping, heterojunction introduction, defect engineering, and so on, to further enhance its HER performance.

Highly efficient NiCo/VN electrocatalyst co-facilitated by interfacial engineering and support effect for large-current-density alkaline water/seawater hydrogen evolution reaction

Developing efficient and continuously stable water electrolysis catalysts to cope with harsh industrial conditions remains a huge challenge in the alkaline seawater electrolysis hydrogen production process. Transition metal nitrides are potential catalysts for seawater electrolysis, but they are still being modified to further improve catalytic performance. Here, a nanosheet-like NiCo/VN heterostructure electrocatalyst was prepared. The heterogeneous interface formed between and VN and NiCo alloy and the strong metal-support interaction regulate the electronic structure and optimizes the adsorption and desorption of intermediates. Moreover, the introduction of the NiCo alloy greatly facilitates the water dissociation step. Therefore, the prepared NiCo/VN catalyst exhibits excellent alkaline HER performance, with a low overpotential of 38 mV and 318 mV at a current density of 10 mA cm−2 and 1000 mA cm−2, shows high durability in 50 h of constant current tests at current densities of 10, 100, and 1000 mA cm−2 in alkaline seawater. This work proposes an effective strategy for preparing multiphase electrocatalysts, and the mechanism research fully confirms that it can promote the dissociation of water and the adsorption and desorption of intermediates.

Ultrafast Quasi-Solid-State Microwave Construction of Spongy Cobalt-Molybdenum Phosphide for Hydrogen Production Over Wide pH Range.

The developed strategies for synthesizing metal phosphides are usually cumbersome and pollute the environment. In this work, an ultrafast (30s) quasi-solid-state microwave approach is developed to construct cobalt-molybdenum phosphide decorated with Ru (Ru/CoxP-MoP) featured porous morphology with interconnected channels. The specific nanostructure favors mass transport, such as electrolyte bubbles transfer and exposing rich active sites. Moreover, the coupling effects between metallic elements, especially the decorated Ru, also act as a pivotal role on enhancing the electrocatalytic performance. Benefiting from the effects of composition and specific nanostructure, the prepared Ru/CoxP-MoP exhibits efficient HER performance with a current density of 10mAcm-2 achieved in 1m KOH, 0.5mH2SO4, seawater containing 1mKOH and 1mPBS, with overpotentials of 52, 59, 55, 90mV, and coupling with good stability. This work opens a novel and fast avenue to design metal-phosphide-based nanomaterials in energy-conversion and storage fields.

Crystal facet/interface anchored Janus activity of BiOBr in driving photocatalytic water splitting

Constructing Janus junctions is expected to provide a novel perspective for analyzing the intrinsic photocatalytic activity of bismuth oxyhalide. Herein, Janus-typed BiOBr(010)/BiOBr(001) homojunction with efficiently photocatalytic H2 evolution has been achieved by a hydrothermal synthesis. The experimental results show that the designed Janus-typed junction can effectively elevate the carrier lifetime, significantly enhance the photocurrent, and prominently reduce the overpotential. The potential difference (0.34 eV) between (010) facet and (001) facet can drive the carrier transport at the interface for Janus junctions. Theoretical calculations indicate that the designed Janus junction has a stable mechanical structure, providing certain support for the long lifetime of the photocatalyst in the photocatalytic process. The carrier distributions in the Janus junction exhibit the typical characteristic distribution. Interestingly, the photo-generated electrons are only localized in BiOBr(001) component, which embodies significantly a role of n-type semiconductor. This essentially activates HER activity (32 µmol/h g−1) of Janus junction. The holes preferentially localize in the BiOBr(010) component of Janus junction. This component undertaking p-type role reduces the free energy of the rate determining step (from OH* to O*) in the oxygen evolution process (0.88 eV). The Janus junction intensively suppresses the carrier recombination probability at the high symmetry point (reciprocal space) in BiOBr. Ab initio molecular dynamics calculations show that the adsorbed water is easy to decompose on the surface of Janus junction. The obtained results of the photocatalytic water splitting further confirm that the designed BiOBr(010)/BiOBr(001) has Janus characteristics, which are consistent with theoretical calculations and tracer tracing results. The diffusion characteristics of hydrogen also evidence that the interaction of the internal electric field in the Janus junction can drive the HER performance. Additionally, these results offer us a unique angle of view to regulate the charge carrier dynamics by the highly oriented facet coupling for the layered semiconductor.

Aspartic acid/ thiourea − derived N and S − doped porous carbon as a metal-free electrocatalyst for oxygen and hydrogen evolution reactions

The preparation of high-efficiency electrocatalysts for the oxygen and hydrogen evolution process (OER and HER) using an easy, green, and facile preparation method is crucial for the effective and economical use of clean energy sources. Heteroatom-doped carbon nanomaterials are effective metal-free electrocatalysts for HER and OER reactions. Herein, N and S co-doped porous carbon nanocomposite (NS-PC) was constructed as a low-cost metal-free catalyst via pyrolysis of the Thiourea and L-aspartic acid. Doping heteroatoms (N and S) into the carbon structure can induce charge redistribution, expose many active sites, accelerate charge transfer, and thus effectively improve the catalytic activity. The NS-PC electrocatalyst demonstrates proper bifunctional electrocatalytic performance for HER and OER with long-term stability in KOH electrolytes. As a result, the NS-PC requires an overpotential of 139 mV and 315 mV in the current density of 10 mA cm– 2 and the Tafel slope of 59.6 and 69.8 mV dec−1 for HER and OER, respectively. As-papered NS-PC electrocatalyst offers the development of multi-functional electrocatalysts in the water splitting process using biological substances such as amino acids.

Low Zn-doped Co3O4 nanorods for enhanced hydrogen evolution reaction

Transition metal oxides have been identified as the best potential candidates to replace Pt-based HER catalysts. But they are still limited by the high HER overpotential, due to the undesirable adsorption/desorption of surface hydrogen. In this work, Zn with low concentrations were incorporated into the tetrahedral Co2+ sites of Co3O4 by hydrothermal and subsequent annealing treatment. They exhibit excellent HER performance. Particularly, when the Zn content in Co3O4 is 6.3 at%, an overpotential of 79.2 mV at the current density of 10 mA cm−2 was obtained in alkaline medium, which significantly better than pure Co3O4 catalyst (196.3 mV). Moreover, the current density of the Zn-doped Co3O4 catalyst can maintained 93 % after 10 h and 80 % after 20 h. DFT calculations reveal that the ΔGH* of Zn-doped Co3O4 (0.827 eV) is smaller and closer to zero than pure Co3O4 (1.023 eV). This work provides a deep insight into the rational design of low-level metal-doped cobalt oxide-based electrocatalysts.