Effect of oxygen vacancy defect regeneration on photocatalytic properties of ZnO nanorods

Abstract

The effect of oxygen vacancy (VO) defect regeneration in ZnO nanorods on their photocatalytic properties has been investigated. The ZnO nanorods with different VO defect concentrations were realized by the annealing in the different atmospheres of vacuum, oxygen, air and Ar. And the VO defect concentrations in the annealed ZnO nanorods follow an order of Cvacuum > CAr > Cair > Coxygen. By the photocatalytic degradation test to methyl orange solution (MO), the photocatalytic performance of the samples is in accordance with the order of VO defect concentration in the samples, that is, the photocatalytic performance of ZnO nanorods increases with the increase of VO defect concentration, and the best performance is achieved in the sample annealed in the vacuum atmosphere due to the highest VO defect concentration. The regeneration ability of VO defects in ZnO nanorods was studied through the oxygen-deficit atmosphere annealing after each cyclic photocatalytic test. Although the photocatalytic performance of ZnO nanorods degrades slightly with the increase of cyclic test numbers, the VO defects regenerated sample still shows excellent photocatalytic performance after three cyclic tests. The results show that the VO defects in ZnO nanorods play a key role in improving the photocatalytic degradation performance, and the VO defects regenerated ZnO nanorods still show good photocatalytic degradation performance, indicating that ZnO can be reused as a photocatalyst by the VO defect regeneration.