Defect‐Mediated S‐Scheme Charge Transfer in CdPS ₃ /Znln ₂ S ₄ Hybrids for Efficient Photocatalytic Hydrogen Generation under Wide‐Spectrum Light Irradiation

Abstract Step‐scheme (S‐scheme) semiconductor heterojunctions have attracted considerable attention in photocatalytic solar energy conversion. However, their photocatalytic activity is still limited by the insufficient light harvesting and carrier separation. In this study, a defect‐engineered S‐scheme heterostructure is presented through the rational construction of sulfur/phosphorus‐deficient CdPS ₃ /ZnIn ₂ S ₄ hybrids for efficient photocatalytic hydrogen generation driven by wide light absorption and efficient charge separation. The synthetic protocol involves initial fabrication of defect‐rich CdPS ₃ nanosheets containing sulfur and phosphorus vacancies, followed by growth of ZnIn ₂ S ₄ nanosheets to establish defective CdPS ₃ /ZnIn ₂ S ₄ hybrids. Under simulated solar irradiation, the hybrids demonstrate exceptional photocatalytic rates, which is 4.45 and 17.79 times of pristine CdPS ₃ and ZnIn ₂ S ₄ , respectively. This performance also surpasses many ternary transition metal phosphorus chalcogenides and ZnIn ₂ S ₄ ‐based photocatalysts. Mechanism studies indicate that the defect states in CdPS ₃ can broaden the light absorption and provide an intermediate energy level to accelerate charge separation in the S‐scheme junction, thereby significantly improving light‐harvesting efficiency and suppressing the charge recombination. Meanwhile, the defects can optimize the hydrogen atomic activation energy and expose more active sites to boost the hydrogen evolution reaction. This work provides fundamental insights into defect‐mediated interfacial engineering strategies for developing high‐performance S‐scheme photocatalysts.