Constructing a Dipole‐Field Assisted S‐Scheme Heterojunction of ZnIn ₂ S ₄ /CoWO ₄ with Sulfur Vacancies for Highly Efficient Photocatalytic Hydrogen Evolution

ABSTRACT Rationally constructing S‐scheme heterojunctions incorporating anion vacancies offers an effective strategy for developing highly efficient photocatalysts. Herein, CoWO ₄ was combined with sulfur vacancy‐engineered ZnIn ₂ S ₄ (ZIS‐X). Owing to its noncentrosymmetric hexagonal structure (space group P 63 mc ), ZIS‐X possesses an intrinsic dipole field, which facilitates more efficient charge separation. The hydrogen evolution rate of the optimized ZIS‐2/CoWO ₄ composite is 11 times higher than that of pure ZIS‐2 and 379 times greater than that of CoWO ₄ alone. Through photoelectrochemical and analytical investigations, we confirmed that the synergistic interaction between sulfur vacancies and the S‐scheme heterojunction significantly enhances charge separation and improves redox efficiency. This research introduces an innovative approach to developing high‐efficiency photocatalysts through the modulation of vacancy concentrations and the formation of heterojunction structures.