Sulfur Vacancy‐Engineered 2D/2D ZnIn ₂ S ₄ /Zn‐TCPP S‐Scheme Heterojunction for Efficient Photocatalytic H ₂ O ₂ Production

ABSTRACT The sustainable and efficient synthesis of hydrogen peroxide (H ₂ O ₂ ) through photocatalysis remains highly desirable but challenging due to sluggish reaction kinetics and charge recombination. Herein, we report a sulfur vacancy‐engineered 2D/2D S‐scheme heterojunction constructed via the in situ growth of sulfur‐vacancy‐rich ZnIn ₂ S ₄ (Vs‐ZIS) nanosheets on Zn‐TCPP (ZT) nanosheets for efficient H ₂ O ₂ production. The intimate heterojunction interface facilitates rapid and directional separation of photogenerated electron–hole pairs while simultaneously retaining strong redox capability. Moreover, experimental results and density functional theory (DFT) calculations reveal that the introduced sulfur vacancies act as critical active sites, which significantly enhance the adsorption and activation of both O ₂ and H ₂ O molecules. As a result, the optimized Vs‐ZIS/ZT‐20 heterojunction photocatalyst achieves a superior photocatalytic H ₂ O ₂ production rate of 658.0 µmol·g ⁻¹ ·h ⁻¹ under visible‐light irradiation (300 W) in pure water without sacrificial electron donors, which is 4.3 and 5.1 times higher than that of pristine Vs‐ZIS and ZT nanosheets, respectively. Crucially, the as‐prepared catalyst exhibits robust photocatalytic activity across diverse water sources, confirming its practical applicability. This work provides new insights into designing defect‐rich S‐scheme photocatalysts for green energy applications.