Integration of a CuO/ZnO heterojunction and Ag@SiO into a photoanode for enhanced solar water oxidation.

Photoelectrochemical water splitting (PEC-WS) has attracted considerable attention owing to its low energy consumption and sustainable nature. Constructing semiconductor heterojunctions with controllable band structure can effectively facilitate photogenerated carrier separation. In this study, a FTO/ZnO/CuO/Ag@SiO photoanode with a CuO/ZnO p-n heterojunction and Ag@SiO nanoparticles is constructed to investigate its PEC-WS performance. Compared with a bare ZnO photoanode, the photocurrent density of the FTO/ZnO/CuO/Ag@SiO photoanode (0.77 mA cm) at 1.23 V exhibits an increment of 88%, and a cathodic shift of 0.1 V for the on-set potential (0.4 V). Detailed photoelectrochemical analyses reveal that the CuO/ZnO p-n heterojunction formed between CuO and ZnO can effectively promote photogenerated carrier separation. The surface plasmonic effect of the Ag@SiO nanoparticles can further promote the photogenerated carrier transfer efficiency, which synergistically improves the PEC-WS performance.