Emerging Trends in CdS‐Based Nanoheterostructures: From Type‐II and Z‐Scheme toward S‐Scheme Photocatalytic H₂ Production

Cadmium sulfide (CdS) based heterojunctions, including type‐II, Z‐scheme, and S‐scheme systems emerged as promising materials for augmenting photocatalytic hydrogen (H 2 ) generation from water splitting. This review offers an exclusive highlight of their fundamental principles, synthesis routes, charge transfer mechanisms, and performance properties in improving H 2 production. We overview the crucial roles of Type‐II heterojunctions in enhancing charge separation, Z‐scheme heterojunctions in promoting redox potentials to reduce electron‐hole (e − /h + ) pairs recombination, and S‐scheme heterojunctions in combining the merits of both type‐II and Z‐scheme frameworks to obtain highly efficient H 2 production. The importance of this review is demonstrated by its thorough comparison of these three configurations, presenting valuable insights into their special contributions and capability for augmenting photocatalytic H 2 activity. Additionally, key challenges and prospects in the practical applications of CdS‐based heterojunctions are addressed, which provides a comprehensive route for emerging research in achieving sustainable energy goals.