Interface Engineering of Mo‐doped Ni2P/FexP‐V Multiheterostructure for Efficient Dual‐pH Hydrogen Evolution and Overall Water Splitting

Abstract Developing highly effective transition metal‐based bifunctional electrocatalysts remains a tremendously challenging task for large‐scale overall water splitting. Herein, a multiheterostructured Mo‐doped Ni 2 P/Fe x P electrocatalyst on NiFe foam with P vacancy (denoted as Mo─Ni 2 P/Fe x P‐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─Ni 2 P/Fe x P‐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 H 2 O 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.