Synthesis of ZnO doped high valence S element and study of photogenerated charges properties

Nonmetal doping is an efficient way to increase the photoresponse range of ZnO. However, the mechanism for improving the light response range of ZnO with nonmetal doping is not clear. Herein, ZnO doped with S was successfully prepared by ion exchange and calcination methods, which resulted in the uniform distribution of sulfur ions in ZnO. The S element doped was mainly S⁴⁺ and S⁶⁺, which was identified by XPS. We studied the influence of S on the photogenerated charge characteristics of ZnO with SPS. Results indicated that the uniform distribution of S dopants elevated the valence band maximum by mixing S 3p with the upper valence band states of ZnO. The valence band maxima of S-ZnO was 0.37 eV higher than that of ZnO. This result was the main reason for the improvement in the light response. We also studied the photocatalytic activity of Ag/S-ZnO. Ag/S-ZnO with 10 wt% Ag loading showed the highest photocatalytic degradation rate for MO. In this paper, a potential photocatalytic mechanism has been proposed.