Crystal surfaces cooperate with F ion migration to improve the photocatalytic performance of Z-type Ag-Ag2S/F-TiO2 composites

Abstract

The TiO2 has the problems of low utilization of visible light and high photogenerated carrier recombination rate. The photocatalytic activity of TiO2 can be significantly improved by introducing F ion and narrow band gap material Ag2S. When F ions are present on the {001} surface of TiO2, surface F ions drive positively charged holes across the {001} surface, creating a synergistic effect that promotes the separation of electron-hole pairs. During the sample composite process, a certain amount of Ag will be precipitated to form an all-solid Z-type heterojunction structure of Ag2S, Ag and F-TiO2, which can improve the electron-hole separation efficiency. The results of XPS characterization confirmed the migration of F ion and the precipitation of Ag. The Ag2S/F-TiO2 composite sample was referred to as AT for short, and the corresponding ratio was 1:10,1:20,1:30,1:40, the optimal sample AT 1:20 degraded 95.6% tetracycline hydrochloride within 2 hours. This work simultaneously realizes TiO2 self-modification (synergistic effect of F ion migration and TiO2{001} crystal surface) and composite modification (formation of all-solid Z-type heterojunction), a new idea of studying TiO2 self-modified cooperative heterostructures is proposed, and the good application potential of AT nanocomposites in photocatalytic water treatment technology is demonstrated.