Z-Scheme ZnO/ZnAlO Heterojunction with Synergistic Effects for Enhanced Photocatalytic CO Reduction.

The photocatalytic reduction of CO into valuable hydrocarbons presents significant potential. In this research, a ZnO/ZnAlO composite photocatalyst was synthesized using the hydrothermal method, resulting in a marked enhancement in CO yield-approximately three times greater than that achieved with pure ZnAlO nanoparticles. The formation of a Z-scheme heterojunction between ZnO and ZnAlO was observed, characterized by low interfacial charge transfer resistance, an abundance of reaction sites, and optimized charge transport pathways. Within this composite, ZnO contributes additional vacancies, thereby increasing active sites and enhancing the separation and migration of photogenerated carriers. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analysis indicates that ZnAlO facilitates the formation of key intermediates, such as *COOH and HCO, thus promoting the conversion of CO to CO. This study offers valuable insights into the design of heterogeneous catalysts with diverse active components to enhance the performance of CO photocatalytic reduction through synergistic effects.