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The crystalline dependent discharge process shows strong structure-reforming ability on surface and promotes the formation of vacancies and thus reducing the adsorption energy of intermediate. [Display omitted] Alkaline water electrolysis is apreferred technology for large-scale green hydrogen production. For most active transition metal-based catalysts during anodic oxygen evolution reaction (OER), the atomic structure of the anodic catalysts' surface often undergoes reconstruction to optimize the reaction path and enhance their catalytic activity. The design and maintenance of highly active sites during this reconstruction process remain critical and challenging for most OER catalysts. In this study, we explored the effects of crystal structures in pre-catalysts on surface reconstruction at low applied potential. Through experimental observation and theoretical calculation, we found out that catalysts with specific crystal structures exhibit superior surface remodeling ability, which enables them to better adapt to the conditions of the oxygen evolution reaction and achieve efficient catalysis. The discharge process enables the formation of abundant phosphorus vacancies on the surface, which in turn affects the efficiency of the entire oxygen evolution reaction. The optimized crystal structure of the catalyst results in an increase as high as 58.5 mA/cm2 for Ni 5 P 4 , which is twice as high as that observed for Ni 2 P. These results provide essential theoretical foundations and technical guidance for designing more efficient catalysts for oxygen evolution reactions. [ABSTRACT FROM AUTHOR]

Schematic diagram representation the introduction of selenium and iron synergistically modulate the d-band center of Ni 3 S 2 to enhance oxygen evolution reaction (OER) and urea oxidation reaction (UOR). [Display omitted] • The introduction of selenium and iron synergistically modulated the d-band center of Ni 3 S 2 , resulting in the enhanced catalytic activity for the oxygen evolution reaction (OER) and urea oxidation reaction (UOR). • By adjusting the position of the d-band center, it is possible to optimize the adsorption and desorption energies of SeFe-Ni 3 S 2 towards urea molecules, as well as the overpotential for OER (η OER) and the limiting potential for UOR (U L). • The synthesized SeFe-Ni 3 S 2 presents as 3.9 nm lamellar structure with a larger specific surface area leading to the exposure of more active sites. Efficient production of green hydrogen energy is crucial in addressing the energy crisis and environmental concerns. The oxygen evolution reaction (OER) poses a challenge in conventional overall water electrolysis due to its slow thermodynamically process. Urea oxidation reaction (UOR) offers an alternative anodic oxidation method that is highly efficient and cost-effective, with favorable thermodynamics and sustainability. Recently, there has been limited research on bifunctional catalysts that exhibit excellent activity for both OER and UOR reactions. In this study, we developed a selenium and iron co-doped nickel sulfide (SeFe-Ni 3 S 2) catalyst that demonstrated excellent Tafel slopes of 53.9 mV dec−1 and 16.4 mV dec−1 for OER and UOR, respectively. Density Functional Theory (DFT) calculations revealed that the introduction of metal (iron) and nonmetallic elements (selenium) was found to coordinate the d-band center, resulting in improved adsorption/desorption energies of the catalysts and reduced the overpotentials and limiting potentials for OER and UOR, respectively. This activity enhancement can be attributed to the altered electronic coordination structure after the introduction of selenium (Se) and iron (Fe), leading to an increase in the intrinsic activity of the catalyst. This work offers a new strategy for bifunctional catalysts for OER and UOR, presenting new possibilities for the future development of hydrogen production and novel energy conversion technologies. It contributes towards the urgent search for technologies that efficiently produce green hydrogen energy, providing potential solutions to mitigate the energy crisis and protect the environment. [ABSTRACT FROM AUTHOR]

A high dispersed 2D NiFeP/CoP heterogeneous catalyst was designed and constructed by in situ transformation from nanorod CoO for catalyzing oxygen evolution reaction, urea oxidation reaction, and hydrogen evolution reaction. [Display omitted] The electrocatalytic production of "green hydrogen", such as through the electrolysis of water or urea has been vigorously advocated to alleviate the energy crisis. However, their electrode reactions including oxygen evolution reaction (OER), urea oxidation reaction (UOR), and hydrogen evolution reaction (HER) all suffer from sluggish kinetics, which urgently need catalysts to accelerate the processes. Herein, we design and prepare an OER/UOR/HER trifunctional catalyst by transforming the homemade CoO nanorod into a two-dimensional (2D) ultrathin heterojunction nickel–iron-cobalt hybrid phosphides nanosheet (NiFeP/CoP) via a hydrothermal-phosphorization method. Consequently, a strong electronic interaction was found among the Ni 2 P/FeP 4 /CoP heterogeneous interfaces, which regulates the electronic structure. Besides the high mass transfer property of 2D nanosheet, Ni 2 P/FeP 4 /CoP displays improved OER/UOR/HER performance. At 10 mA cm−2, the OER overpotential reaches 274 mV in 1.0 M KOH, and the potential of UOR is only 1.389 V in 1.0 M KOH and 0.33 M urea. More strikingly, the two-electrode systems for electrolysis water and urea-assisted electrolysis water assembled by NiFeP/CoP could maintain long-term stability for 35 h and 12 h, respectively. This work may help to pave the way for upcoming research horizons of multifunctional electrocatalysts. [ABSTRACT FROM AUTHOR]

In this work, a unique tri-metal (Co/Fe/Ni) layered double hydroxide hollow array anode catalyst (CFN-LDH/NF) and the CoP/FeNi 2 P heterojunction hollow array cathode are successfully prepared via one in-situ growth of Co-MOF on nickel foam (Co-MOF/NF) precursor, which exhibits excellent catalytic performance of OER η 1000 (CFN-LDH/NF) of 352 and 392 mV in 1.0 M KOH and alkaline seawater solution and HER η 1000 (CFNP/NF) of 281 and 312 mV in 1.0 M KOH and alkaline seawater solution. [Display omitted] The seawater electrolysis technology powered by renewable energy is recognized as the promising "green hydrogen" production method to solve serious energy and environmental problems. The lack of low-cost and ampere-level current OER (oxygen evolution reaction) and HER (hydrogen evolution reaction) catalysis limits their industrial application. In this work, a unique tri-metal (Co/Fe/Ni) layered double hydroxide hollow array anode catalyst (CFN-LDH/NF) and the CoP/FeNi 2 P heterojunction hollow array cathode are successfully prepared via one in-situ growth of Co-MOF on nickel foam (Co-MOF/NF) precursor, which exhibits excellent catalytic performance. The η 1000 values of 352 and 392 mV are achieved for CFN-LDH/NF (OER catalyst) in 1.0 M KOH and alkaline seawater solution, respectively. The CFNP/NF with a low overpotential of 281 mV is required to reach 1000 mA cm−2 current density for HER in 1.0 M KOH solution, while the η 1000 in alkaline seawater solution is 312 mV. The CFN-LDH/NF||CFNP/NF electrolyzer exhibits excellent long-term durability over 100 h, achieving current density of 500 mA cm−2 at 1.825 V in 1.0 M KOH solution. The construction of hollow tri-metal LDH and phosphides heterostructures may open a new and relatively unexplored path for fabricating high performance seawater splitting catalysis. [ABSTRACT FROM AUTHOR]

An efficient Pt active site anchored strategy is developed for MnCo 2 O 4 nanosheet arrays, which is standing for excellent bifunctional electrode for hydrogen production by ampere-level hydrazine assisted water electrolysis. [Display omitted] Coupling hydrazine oxidation reaction (HzOR) with hydrogen evolution reaction (HER) has been widely concerned for high efficiency of green hydrogen preparation with low energy consumption. However, the lacking of bifunctional electrodes with ampere-level performance severely limits its industrialization. Herein, we put forward an efficient active site anchored strategy for MnCo 2 O 4 nanosheet arrays on nickel foam (NF) by introducing Pt species (denoted as Pt-MnCo 2 O 4 /NF), which is standing for excellent bifunctional electrodes. The Pt-MnCo 2 O 4 /NF delivers ultralow potentials of −195 mV and 350 mV at 1000 mA cm−2 as well as robust stability for HzOR and HER, respectively. The study of in-situ Raman and reaction kinetics reveal that the formation of key adsorbed *NH 2 and *N 2 H 4 intermediates and the rapidly oxidization of intermediates with a fast interfacial charge transfer on Pt-MnCo 2 O 4 /NF. Remarkably, the Pt-MnCo 2 O 4 /NF assembled two-electrode hydrazine assisted water electrolyzer realizes current density of 100 mA cm−2 and 1000 mA cm−2 at 0.16 V and 0.62 V with over 80 h stability. This work provides a promising way to design efficient electrodes for energy-saving H 2 generation under ampere-level current density. [ABSTRACT FROM AUTHOR]

CoFe-LDH/IF was prepared through the self-corrosion engineering of iron foam, and the CoP 2 -FeP 4 heterojunction was synthesized through phosphating and carburizing processes, forming an interfacial charge distribution and achieving efficient and stable water oxidation for 1000 h. [Display omitted] Electrochemical water splitting stands out as a promising avenue for green hydrogen production, yet its efficiency is fundamentally governed by the oxygen evolution reaction (OER). In this work, we investigated the growth mechanism of CoFe hydroxide formed by in situ self-corrosion of iron foam for the first time and the significant influence of dissolved oxygen in the immersion solution on this process. Based on this, the CoP 2 -FeP 4 /IF heterostructure catalytic electrode demonstrates exceptional OER activity in a 1 M KOH electrolyte, with an overpotential of only 253 ± 4 mV (@10 mA cm−2), along with durability exceeding 1000 h. Density functional theory calculations indicate that constructing heterojunction interfaces promotes the redistribution of interface electrons, optimizing the free energy of adsorbed intermediate during the water oxidation process. This research highlights the importance of integrating self-corroding in-situ growth with interface engineering techniques to develop efficient water splitting materials. [ABSTRACT FROM AUTHOR]

[Display omitted] Electrocatalytic water splitting produces green and pollution-free hydrogen as a clean energy carrier, which can effectively alleviate energy crisis. In this paper, bimetallic and selenium doped cobalt molybdate (Se-CoMoO 4) nanosheets with rough surface are resoundingly prepared. The multihole Se-CoMoO 4 nanosheets display ultrathin and rectangular architecture with the dimensions of ∼ 3.5 μm and 700 nm for length and width, respectively. The Se-CoMoO 4 electrocatalyst shows remarkable water electrolysis activity and stability. The overpotentials of oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are 270 and 63.3 mV at 10 mA cm−2, along with low Tafel slopes of 51.6 and 62.0 mV dec-1. Furthermore, the Se-CoMoO 4 couple electrolyzer merely requires a cell voltage of 1.48 V to achieve 10 mA cm−2 current density and presents no apparent attenuation for 30 h. This investigation declares that the hybridization of transition bimetallic oxide with nonmetallic adulteration can afford a tactic for the preparation of bifunctional non-precious metal-based electrocatalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • ·Mo 2 C-FeCu catalyst was designed by thermal reduction and carburization of precursor. • ·cinnamaldehyde/benzalacetone were synthesized at high yields and selectivities. • · α , β -unsaturated aldehyde/ketone were electrosynthesized in gentle and green manner. • ·C C coulping reaction was fulfilled by combined electrochemical-chemical pathway. Oxygen evolution reaction (OER) is the efficiency limiting half-reaction in water electrolysis for green hydrogen production due to the 4-electron multistep process with sluggish kinetics. The electrooxidation of thermodynamically more favorable organics accompanied by C C coupling is a promising way to synthesize value-added chemicals instead of OER. Efficient catalyst is of paramount importance to fulfill such a goal. Herein, a molybdenum iron carbide-copper hybrid (Mo 2 C-FeCu) was designed as anodic catalyst, which demonstrated decent OER catalytic capability with low overpotential of 238 mV at response current density of 10 mA cm−2 and fine stability. More importantly, the Mo 2 C-FeCu enabled electrooxidation assisted aldol condensation of phenylcarbinol with α -H containing alcohol/ketone in weak alkali electrolyte to selective synthesize cinnamaldehyde/benzalacetone at reduced potential. The hydroxyl and superoxide intermediate radicals generated at high potential are deemed to be responsible for the electrooxidation of phenylcarbinol and aldol condensation reactions to afford cinnamaldehyde/benzalacetone. The current work showcases an electrochemical-chemical combined C C coupling reaction to prepare organic chemicals, we believe more widespread organics can be synthesized by tailored electrochemical reactions. [ABSTRACT FROM AUTHOR]

[Display omitted] The construction of binder-free electrodes with well-defined three-dimensional (3D) morphology and optimized electronic structure represents an efficient strategy for the design of high-performance electrocatalysts for the development of efficient green hydrogen technologies. Herein, Ru nanocrystals were modified on 3D interconnected porous FeOOH nanostructures with open network-like frameworks on NiFe foam (Ru/FeOOH@NFF), which were used as an efficient electrocatalyst. In this study, a 3D interconnected porous FeOOH with an open network structure was first electrodeposited on NiFe foam and served as the support for the in-situ modification of Ru nanocrystals. Subsequently, the Ru nanocrystals and abundant oxygen vacancies were simultaneously incorporated into the FeOOH matrix via the adsorption-reduction method, which involved NaBH 4 reduction. The Ru/FeOOH@NFF electrocatalyst shows a large specific surface area, abundant oxygen vacancies, and modulated electronic structure, which collectively result in a significant enhancement of catalytic properties with respect to the oxygen evolution reaction (OER) and urea oxidation reaction (UOR). The Ru/FeOOH@NFF catalyst exhibits an outstanding OER performance, requiring a low overpotential (360 mV) at 200 mA cm−2 with a small Tafel slope (58 mV dec-1). Meanwhile, the Ru/FeOOH@NFF catalyst demonstrates more efficient UOR activity for achieving 200 mA cm−2 at a lower overpotential of 272 mV. Furthermore, an overall urea electrolysis cell using the Ru/FeOOH@NFF as the anode and Pt as the cathode (Ru/FeOOH@NFF||Pt) reveals a cell voltage of 1.478 V at 10 mA cm−2 and a prominent durability (120 h at 50 mA cm−2). This work will provide a valuable understanding of the construction of high-performance electrocatalysts with 3D microstructure for promoting urea-assisted water electrolysis. [ABSTRACT FROM AUTHOR]

[Display omitted] The pursuit of efficient and sustainable hydrogen production through water splitting has led to intensive research in the field of electrocatalysis. However, the impediment posed by sluggish reaction kinetics has served as a significant barrier. This challenge has inspired the development of electrocatalysts characterized by high activity, abundance in earth's resources, and long-term stability. In addressing this obstacle, it is imperative to meticulously fine-tune the structure, morphology, and electronic state of electrocatalysts. By systematically manipulating these key parameters, the full potential of electrocatalysts can unleash, enhancing their catalytic activity and overall performance. Hence in this study, a novel heterostructure is designed, showcasing core–shell architectures achieved by covering W 2 N-WC nanowire arrays with tri-metallic Nickel-Cobalt-Iron layered triple hydroxide nanosheets on carbon felt support (NiCoFe-LTH/W 2 N-WC/CF). By integrating the different virtue such as binder free electrode design, synergistic effect between different components, core–shell structural advantages, high exposed active sites, high electrical conductivity and heterostructure design, NiCoFe-LTH/W 2 N-WC/CF demonstrates striking catalytic performances under alkaline conditions. The substantiation of all the mentioned advantages has been validated through electrochemical data in this study. According to these results NiCoFe-LTH/W 2 N-WC/CF achieves a current density of 10 mA cm−2 needs overpotential values of 101 mV for HER and 206 mV for OER, respectively. Moreover, as a bi-functional electrocatalyst for overall water splitting, a two-electrode device needs a voltage of 1.543 V and 1.569 V to reach a current density of 10 mA cm−2 for alkaline water and alkaline seawater electrolysis, respectively. Briefly, this research with attempting to combination of different factors try to present a promising stride towards advancing bi-functional catalytic activity with tailored architectures for practical green hydrogen production via electrochemical water splitting process. [ABSTRACT FROM AUTHOR]

[Display omitted] • A Mn-doped nickel iron layered double hydroxides (Mn-doped NiFe-LDH) supported on nickel foam was developed, and could act as an efficient bifunctional catalyst for the coupling MOR and HER. • The methanol-to-formate faradaic efficiency was determined to be 99.5 % at an external potential of 1.5 V versus reversible hydrogen electrode. • This electrocatalyst is able to drive a current density of 131.1 mA cm−2 with a decay of merely 12.2 % over continuous 120 h testing in co-electrocatalysis of water/methanol solution. Electrochemical upgrading methanol into value-added formate at the anode in alkaline media enables the boosting production of hydrogen fuel at the cathode with saved energy. To achieve such a cost-effective and efficient electrocatalytic process, herein this work presents a Mn-doped nickel iron layered double hydroxides supported on nickel foam, derived from a simple hydrothermal synthesis. This developed electrocatalyst could act as an efficient bifunctional electrocatalyst for methanol-to-formate with a high faradaic efficiency of nearly 100 %, and for hydrogen evolution reaction, at an external potential of 1.5 V versus reversible hydrogen electrode. Additionally, a current density of 131.1 mA cm−2 with a decay of merely 12.2 % over 120 h continuous long-term testing was generated in co-electrocatalysis of water/methanol solution. Further density functional theoretical calculations were used to unravel the methanol-to-formate reaction mechanism arising from the doping of Fe and/or Mn. This work offers a good example of co-electrocatalysis to produce formate and green hydrogen fuel using a bifunctional electrocatalyst. [ABSTRACT FROM AUTHOR]

[Display omitted] Developing efficient and stable electrocatalysts at affordable costs is very important for large-scale production of green hydrogen. In this study, unique amphoteric metallic element-doped NiFe-LDH nanosheet arrays (NiFeCd-LDH, NiFeZn-LDH and NiFeAl-LDH) using as high-performance bifunctional electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) were reported, by tuning electronic structure and vacancy engineering. It was found that NiFeCd-LDH possesses the lowest overpotentials of 85 mV and 240 mV (at 10 mA cm−2) for HER and OER, respectively. Density functional theory (DFT) calculations reveal the synergistic effect of Cd vacancies and Cd doping on improving alkaline HER performance, which promote the achievement of excellent catalytic activity and ultrastable hydrogen production at a large current density of 1000 mA cm−2 within 250 h. Besides, the overall water splitting performance of the as-prepared NiFeCd-LDH requires only 1.580 V to achieve a current density of 10 mA cm−2 in alkaline seawater media, underscoring the importance of modifying the electronic properties of LDH for efficient overall water splitting in both alkaline water/seawater environments. [ABSTRACT FROM AUTHOR]

[Display omitted] • Facile synthesis of structurally engineered Ternary Spinel-type NiFeCoO 4 nanoparticles. • Ni-Fe-Co elements work synergistically to enhance the electrocatalytic activity. • The defect engineered NiFeCoO 4 requires a low water splitting cell voltage of 1.67 V. Transition metal spinel oxides were engineered with active elements as bifunctional water splitting electrocatalysts to deliver superior intrinsic activity, stability, and improved conductivity to support green hydrogen production. In this study, we reported the ternary metal Ni-Fe-Co spinel oxide electrocatalysts prepared by defect engineering strategy with rich and deficient Na+ ions, termed NFCO-Na and NFCO, which suggest the formation of defects with Na+ forming tensile strain. The Na-rich NiFeCoO 4 spinel oxide reveals lattice expansion, resulting in the formation of a defective crystal structure, suggesting higher electrocatalytic active sites. The spherical NFCO-Na electrocatalysts exhibit lower OER and HER overpotentials of 248 mV and 153 mV at 10 mA cm−2 and smaller Tafel slope values of about 78 mV dec−1 and 129 mV dec−1, respectively. Notably, the bifunctional NFCO-Na electrocatalyst requires a minimum cell voltage of about 1.67 V to drive a current density of 10 mA cm−2. The present work highlights the significant electrochemical activity of defect-engineered ternary metal oxides, which can be further upgraded as highly active electrocatalysts for water splitting applications. [ABSTRACT FROM AUTHOR]

A hydrogen-bonded organic framework (HOF) nanowire was developed as a precursor and template for the synthesis of CoRu-MOF nanotubes and densely isolated CoRu alloy catalysts. The optimized Co-15Ru@NG-500 catalyst demonstrated superior catalytic performance for the HER in alkaline electrolytes with an overpotential of only 30 mV at 10 mA cm−2 and robust durability. [Display omitted] Designing highly efficient and stable electrocatalysts for hydrogen evolution reactions (HER) is essential to the production of green and renewable hydrogen. Metal-organic framework (MOF) precursor strategies are promising for the design of excellent electrocatalysts because of their porous architectures and adjustable compositions. In this study, a hydrogen-bonded organic framework (HOF) nanowire was developed as a precursor and template for the controllable and scalable synthesis of CoRu-MOF nanotubes. After calcination in Ar, the CoRu-MOF nanotubes were converted into N -doped graphene (NG) nanotubes with ultrafine CoRu nanoclusters (hereon called Co- x Ru@NG- T ; x = 0, 5, 10, 15, 25 representing the Ru content of 0–0.25 mmol; T = 400 °C to 700 °C) that were densely encapsulated and isolated on the shell. Taking advantage of the synergistic effects of the porous, one-dimensional hollow structure and ultrafine CoRu nanoclusters, the optimized Co-15Ru@NG-500 catalyst demonstrated superior catalytic performance for HERs in alkaline electrolytes with an overpotential of only 30 mV at 10 mA cm−2 and robust durability for 2000 cycles, which outperforms many typical catalytic materials, such as commercial Pt/C. This work introduces a novel high-efficiency and cost-effective HER catalyst for application in commercial water-splitting electrolysis. [ABSTRACT FROM AUTHOR]

A novel Fe, Co-CeO 2 /CeF 3 @MXene heterostructure with Fe-Co dual active sites and oxygen vacancies has been prepared for alkaline water/real seawater OER. [Display omitted] • Fe, Co-CeO 2 /CeF 3 @MXene heterostructure with Fe-Co dual active sites was synthesized by energy-free consumption co-deposition method. • Fe，Co-CeO 2 /CeF 3 @MXene can function as highly effective electrocatalyst toward OER. • The adsorption evolution mechanism and the lattice oxygen mechanism synergistically enhanced the OER activity. • Wind and solar-energy-assisted water electrolysis devices show their promising prospects for green hydrogen production sustainably. Exploring low-cost, high-activity, and structurally stable nonprecious metal electrocatalysts for sluggish oxygen evolution reaction (OER) is paramount for water electrolysis. Herein, we successfully prepare a novel Fe,Co-CeO 2 /CeF 3 @MXene heterostructure with Fe–Co dual active sites and oxygen vacancies for alkaline OER using an energy-free consumption co-deposition method. Impressively, Fe,Co-CeO 2 /CeF 3 @MXene achieves an ultralow overpotential of 192 mV and a long-term stability of 110 h at 10 mA cm−2 without structural changes, thereby outperforming the commercial IrO 2 (345 mV). In addition, Fe,Co-CeO 2 /CeF 3 @MXene exhibits much superior activity (271 mV) and durability to IrO 2 (385 mV) in the real seawater OER. Wind- and solar energy-assisted water electrolysis devices show their promising prospects for sustainable green hydrogen production. Characterization techniques and theoretical calculations reveal that the Fe,Co co-implanted CeO 2 /CeF 3 heterostructure effectively degrades the energy barrier of the OER and optimizes the adsorption strength of *OH, *O, and *OOH intermediates. It exhibits the dual coupling mechanism of the adsorbed evolution and lattice oxygen mechanisms, which synergistically improves the OER performance. This work provides a facile and efficacious strategy for synthesizing a new class of heterostructures to achieve significant enhancement in the activity and stability of OER catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nanoneedle catalysts with core-shell structure were formed at room temperature. • CeO 2 adjusted and optimized the electronic structure of transition metal phosphides. • The catalysts exhibited excellent catalytic activities for both HER and OER. • The synthesized catalysts exhibited good structural stability. The discovery of earth-abundant electrocatalysts to replace platinum and iridium for overall water splitting is a crucial step in reducing the cost of green hydrogen production. Transition metal phosphides have drawn wide attention due to their non-toxicity, good chemical stability, low cost, and stable catalytic activity in alkaline electrolytes. We report a three-dimensional flower-like structure composed of core-shell nanoneedles as catalysts, in which CeO 2 is introduced on the surface of nickel cobalt bimetallic phosphide through electrodeposition. And X-ray photoelectron spectroscopy testing and DFT calculations show electron coupling and transfer between CeO 2 and CoP 3 , thereby modulating the electronic structure of the catalyst surface and reducing the adsorption energy of H atoms during the catalytic process, resulting in enhanced catalytic activity. In 1 M KOH, it exhibits a low overpotential of 109 and 296 mV to achieve the current density of 50 mA cm−2 for HER and OER, respectively. When used as both cathode and anode as a bifunctional catalyst, a voltage of only 1.77 V is required to achieve a current density of 50 mA cm−2, demonstrating great industrial potential. [ABSTRACT FROM AUTHOR]