Research progress on the construction of oxygen vacancy defects and application in photocatalytic oxidation of elemental mercury

As a common crystal defect, oxygen vacancy has a significant effect on the optical properties of semiconductor photocatalysts. Improving the photocatalytic activity of photocatalysts by introducing and regulating oxygen vacancy is one of the current research focuses. Meanwhile, oxygen vacancies can capture and activate molecular oxygen, which plays an important role in the photocatalytic oxidation of elemental mercury. In this review, the preparation and characterization methods of oxygen vacancy are reviewed systematically and the mechanism of photocatalytic oxidation of elemental mercury is revealed in detail. In addition, the mechanism of the effect of oxygen vacancy in optimizing the energy band structure, promoting carrier separation, surface reactions and changing the electron transfer path is discussed in depth. Finally, the future development prospects of oxygen vacancies in the field of photocatalytic oxidation of elemental mercury are prospected. This work can provide valuable theoretical reference and scientific basis for the design and research of photocatalysts containing oxygen vacancies.