Construction of CdxZn1-xS for H2 production coupled with benzyl alcohol oxidation: Regulation of electrophilic and nucleophilic properties.

Photocatalytic hydrogen evolution coupled with selective benzyl alcohol oxidation offers a promising route for concurrent value-added chemical synthesis and clean energy production. However, the overall efficiency of this process is significantly limited by the inefficient generation and non-directional migration of photogenerated electron-hole pairs. To address these challenges, this study designed and constructed a novel CdxZn1-xS catalyst via a one-step hydrothermal method for visible light-driven photocatalytic hydrogen evolution and benzyl alcohol oxidation, without the addition of a sacrificial agent. The effects of the Cd/Zn ratio on the catalyst's band structure and the behavior of photogenerated electron-hole pairs were systematically investigated through experimental characterizations and density functional theory calculations. The results reveal that the introduction of bimetallic sites in the CdxZn1-xS solid solution creates distinct electrophilic and nucleophilic regions. This unique electronic structure modulates the energy band structure, thereby extending the light absorption range and enhancing the generation of photogenerated charge carriers. More importantly, it facilitates the directional migration of photogenerated electrons and holes to their respective reaction sites, which reduces charge recombination and ensures efficient reaction completion. Thus, the optimized CdxZn1-xS catalyst exhibited a high photocatalytic activity of H2 (9.33 mmol/(g⋅h)) and benzaldehyde yield (10.01 mmol/(g⋅h)) under visible light irradiation. This work provides new insights for designing efficient dual-functional photocatalysts for sustainable energy conversion and organic synthesis.