Hierarchical Co₉S₈/CdS Hollow Nanocages for Efficient and Robust Cooperative Coupling Photoredox Synthesis

The elaborate development of photocatalysts that can maximize the utility of solar energy with simultaneous photocatalytic H₂ evolution and high-quality chemicals production holds great promise in the field of selective photoredox synthesis. Herein, the in situ growth of CdS nanowires on the outside surface of Co₉S₈ hollow nanocages is reported to create a hierarchical CdS/Co₉S₈ hollow photocatalyst for efficient photochemical coupling of amines to produce imines and H₂. This ingenious hierarchical photocatalyst has a unique hollow structure and dense interfacial contact with a type-I band orientation, which facilitates the interfacial transfer of charge carriers. The photocatalytic activity of this hierarchical hollow catalyst is significantly enhanced in comparison to CdS and Co₉S₈, and distinctively exhibits excellent recycling stability. Mechanistic studies have shown that the carbon-centered radical Ph(^•CH)NH₂ is essential for the reaction. Additionally, the CdS/Co₉S₈ hollow hybrid also exhibits outstanding performance in coupling various primary amines to the corresponding imines, highlighting the broad applicability of this photocatalyst for C-N coupling reactions. This work offers a new strategy for the efficient design of heterostructured hollow semiconductor-based photocatalysts for the cooperative coupling of clean fuel production and fine chemical synthesis.