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

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