Constructing an Ag Doping MoS ₂ /NiCoP Heterojunction With a Built‐In Electric Field for Efficient Overall Water Splitting

The construction of n–n heterojunctions modulates the electronic structure of transition metals and enhances interfacial electron transfer, but designing efficient heterojunction‐based catalysts for overall water splitting remains challenging. Here, MoS 2 and NiCoP integrate to construct a built‐in electric field, and modification with Ag nanoparticles(NPs) endows the catalyst with superior hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performance. Benefiting from the synergistic interplay among MoS 2 , NiCoP, and Ag NPs, the Ag‐MoS 2 /NiCoP@NF catalyst exhibits outstanding bifunctional activity, requiring overpotentials of 115 mV (HER) and 180 mV (OER) at 10 mA cm −2 . It enables overall water splitting at a low cell voltage of 1.57 V at 10 mA cm −2 and demonstrates excellent durability, with only 5% performance decay after 50 h. Contact between semiconductors with distinct electronic structures generates a stable built‐in electric field at the interface, establishing thermodynamic equilibrium and promoting charge redistribution during OER and HER. Ag NPs intercalate into the interlayer gaps of MoS 2 . Their uniform dispersion creates additional active interfaces and lowers the reaction overpotential. This work demonstrates a feasible strategy for modulating interfacial electronic structures by synergizing Ag incorporation with heterojunction engineering, providing an effective route for designing high‐performance bifunctional catalysts.