Research progress on the formation, detection methods and application in photocatalytic reduction of CO2 of oxygen vacancy

Photocatalytic reduction of CO2 to valuable carbon products is a very attractive method for energy regeneration and storage, which is also expected to reduce increasing carbon dioxide emissions. Because CO2 molecules is very stable, varied strategies has been developed to design photocatalysts to promote the adsorption and activation of CO2. Among, oxygen vacancy engineering can improve carrier diffusion efficiency, induce the enrichment of electrons, and promote CO2 molecule chemisorption and activation. Therefore, revealing the mechanism of oxygen vacancy is very important for the development of high-efficient photocatalyst. This review briefly in-troduces the principle of photocatalytic reduction of CO2 on the semiconductor with oxygen vacancies. The methods for creating oxygen vacancies and the detection means of oxygen vacancy are summarized. Besides, the mechanism of oxygen vacancy for improving photocatalytic CO2 reduction, such as optimizing the bandgap of semiconductor, improving the transmission efficiency of carriers, and adsorbing and activating CO2 molecules has been deeply discussed. Finally, the development prospects of oxygen vacancy in photocatalytic reduction of CO2 are also prospected. This review could provide an effective reference for researchers to better understand the research progress and development trend of oxygen vacancy in the photocatalytic CO2 reduction.