Iron Incorporation‐Induced Phosphorus Vacancies in MoP: A Dual‐Functional Strategy Toward Efficient Solar Driven Hydrogen Production

ABSTRACT Internal modification represents an effective strategy to enhance the photocatalytic hydrogen evolution performance, where the synergistic effects of doping engineering and vacancy engineering collectively regulate charge transfer dynamics to improve hydrogen evolution efficiency. Through the incorporation of Fe atoms into MoP, phosphorus vacancies (Vp) are generated, which effectively modulate photogenerated carrier separation efficiency. Comprehensive experimental results and theoretical simulations elucidate the mechanism of Fe‐substitution‐induced Vp formation and its subsequent enhancement of photocatalytic hydrogen evolution. The preferential substitution of Fe atoms for Mo sites triggered Vp generation, where Fe 3d orbitals replace Mo 4d orbitals to attract electrons, while Vp acts as electron traps and Mo atoms serve as hole traps, collaboratively optimizing regional charge separation. Furthermore, Fe incorporation increases the catalyst's active surface area, providing more active sites for hydrogen evolution. The optimized Fe‐MoP‐3 catalyst achieves a hydrogen evolution rate of 150.84 µmol/g, representing a 2.72‐fold enhancement compared to pristine MoP (55.26 µmol/g). This work reveals the atomic substitution behavior mechanism and provides fundamental insights for rational design of hydrogen evolution catalysts.