As an effective strategy to improve photocatalytic hydrogen evolution, S-scheme heterojunctions face the fundamental challenge of inefficient photogenerated charge separation. This study constructs a NiPS /CdS (NPS/ CS) S-scheme system and systematically investigates the influence of different defect engineering approaches on interfacial charge transfer. Characterization reveals that nickel vacancy-modified NiPS rupts the original heterojunction structure, while sulfur/phosphorus vacancy-regulated NiPS 3 3 /CdS (V Ni-NPS/CS) dis /CS) maintains the S-scheme band alignment while significantly enhancing charge separation through defect engi neering. Under simulated solar irradiation, NPS-V 3 /CdS (NPS-V PS PS /CS exhibits exceptional photocatalytic hydrogen evolution activity (18.24 mmol/g) with an apparent quantum efficiency of 12.11 %, demonstrating excellent broad- spectrum responsiveness. Mechanistic studies indicate that the introduced P/S vacancies in NPS-V /CS not only serve as electron traps to suppress charge recombination but more importantly, establish intermediate energy levels that accelerate interfacial charge transfer while preserving the S-scheme band structure, thereby remarkably improving hydrogen evolution kinetics. This work provides new insights into the regulatory mechanisms of cation/anion vacancies on heterojunction interface engineering.

https://www.sciencedirect.com/science/article/pii/S0926337325008094?via%3Dihub