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Developing highly effective transition metal‐based bifunctional electrocatalysts remains a tremendously challenging task for large‐scale overall water splitting. Herein, a multiheterostructured Mo‐doped Ni2P/FexP electrocatalyst on NiFe foam with P vacancy (denoted as Mo─Ni2P/FexP‐V/NFF) is developed to serve as an efficient dual‐pH electrocatalyst. Due to the synergistic effect of multiple strategies (heteroatom doping, heterointerface, and P vacancy), the Mo─Ni2P/FexP‐V/NFF possesses remarkable hydrogen evolution reaction (HER) catalytic activity in alkaline/acidic and excellent oxygen evolution reaction (OER) in alkaline media, along with encouraging durability. The mechanisms of improved electrocatalytic activity combining multicharacterizations and density functional theory (DFT) calculations are elucidated. Specifically, X‐ray absorption fine structure experimental analysis confirms that the Mo doping can optimize the electronic structure of electrocatalyst. In situ Raman spectroscopy demonstrates that the evolved oxyhydroxides are the real active substances for the OER. DFT calculations reveal that the conductivity of as‐prepared samples can be enhanced through multiple strategy synergy. Moreover, in the HER process, multiple strategies can not only reduce the hydrogen binding energy to near zero but also enhance the H2O dissociation and *OH desorption. In the OER process, DFT calculations also verify that Mo doping and interface engineering can optimize the adsorption of the rate‐determining step, achieving the lowest theoretical overpotential. [ABSTRACT FROM AUTHOR]

Recently, perovskite (ABO3) nanomaterials have been widely explored as a class of versatile electrocatalysts for oxygen evolution reactions (OER) due to their remarkable compositional flexibility and structural tunability, but their poor electrical conductivity hinders hydrogen evolution reaction (HER) activity and further limits the large-scale application of perovskite oxide in overall water splitting (OWS). In this study, hollow-nanotube-structure LaxCo0.4Fe0.6O3−δ (x = 1.0, 0.9, and 0.8) perovskites with superior HER/OER activity were synthesized on nickel-iron alloy foam (denoted LaxCoFe/NFF) using hydrothermal with a subsequent calcination strategy. Among them, La0.9CoFe/NFF not only exhibited extraordinary HER electrocatalytic performance (160.5 mV@10 mA cm−2 and 241.0 mV@100 mA cm−2) and stability (20 h@10 mA cm−2), but also displayed significant OER electrocatalytic activity (234.7 mV@10 mA cm−2 and 296.1 mV@100 mA cm−2) and durability (20 h@10 mA cm−2), outperforming many recently reported HER/OER perovskite catalysts. The increase in oxygen vacancies caused by the introduction of La deficiency leads to the expansion of the lattice, which greatly accelerates the HER/OER process of La0.9CoFe/NFF. Additionally, the naturally porous skeleton can prevent catalysts from aggregating as well as delay the corrosion and dissolution of catalysts in the electrolyte under high applied potentials. Furthermore, the assembled two-electrode configuration, utilizing La0.9CoFe/NFF (cathode and anode) electrodes, only requires a low cell voltage of 1.573 V at 10 mA cm−2 for robust alkaline OWS, accompanied by remarkable durability over 20 h. This work provides inspiration for the design and preparation of high-performance and stable bifunctional perovskite electrocatalysts for OWS. [ABSTRACT FROM AUTHOR]

The search for low-cost, high-performance, and robust stability bifunctional electrocatalysts to substitute noble metals-based counterparts for overall water splitting to generate clean and sustainable hydrogen energy is of great significance and challenges. Herein, a high-efficient bi-functional nickel–iron phosphide on NiFe alloy foam (denoted as e-NFP/NFF) with 3D coral-like nanostructure was controllably constructed by means of alkali etching and the introduction of non-metallic atoms P. The unique superhydrophilic coral-like structure can not only effectively facilitate the exposure of catalytic active sites and increase the electroactive surface area, but also accelerate charge transport and bubble release. Furthermore, owing to the synergistic effect between the bicomponent of nickel–iron phosphides as well as the strong electronic interactions of the multiple metal sites, the as-fabricated catalyst behaves with excellent bifunctional performance for the hydrogen evolution reaction (overpotentials of 132 and 286 mV at 10 and 300 mA·cm−2, respectively) and oxygen evolution reaction (overpotentials of 181 and 303 mV at 10 and 300 mA·cm−2, respectively) in alkaline electrolytes. Impressively, cells with integrated e-NFP/NFF electrodes as a cathode and anode require only a low cell voltage (1.58 V) to drive a current density of 10 mA·cm−2 for overall water splitting, along with remarkable stability in long-term electrochemical durability tests. This study provides a tunable synthetic strategy for the development of efficient and durable non-noble metal bifunctional catalysts based on the construction of an elaborate structure framework and rational design of the electronic structure. [ABSTRACT FROM AUTHOR]