Changes in photocatalytic activity and optical properties of ZnO whiskers induced by UV irradiation

Controlling the surface properties of ZnO micro-nanostructured materials by surface engineering is a current research hotspot. The tetrapod-like ZnO whisker is a multifunctional material, which has applications in many fields. In this research, ZnO whiskers were first prepared by reactive evaporation, and then the surface properties of the ZnO whiskers were changed by ultraviolet (UV) irradiation. The experimental results show that many oxygen vacancies (VO) are generated on the ZnO whiskers surface under UV irradiation. The presence of surface VO is confirmed by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and photoluminescence spectroscopy. It is found that an appropriate amount of surface VO can enhance the photocatalytic activity of ZnO whiskers. This is chiefly ascribed to two factors: (1) a moderate amount of surface VO is beneficial to the sep-aration of photogenerated electrons and holes; (2) the existence of VO improves the light absorption in the visible light region.

Automated summary

This research prepares ZnO whiskers through reactive evaporation and alters their surface properties by ultraviolet irradiation. The experimental results reveal that numerous oxygen vacancies are generated on the surface of ZnO whiskers under UV irradiation. The presence of surface oxygen vacancies enhances the photocatalytic activity of ZnO whiskers.