Design Ag-doped ZnO heterostructure photocatalyst with sulfurized graphitic C3N4 showing enhanced photocatalytic activity

Abstract

Highly efficient Ag-doped ZnO (Ag-ZnO)/sulfurized graphitic C3N4 heterostructure photocatalyst was synthesized in a two-step hydrothermal route. Initially, Ag (1–9%) was doped into ZnO nanostructure and checked photocatalytic properties. 7% Ag-doped ZnO (7Ag-ZnO) NPs shown best photocatalytic methylene blue (MB) dye degradation under visible radiation, so, it was selected for forming composite with S-g-C3N4. In 1st step, S-g-C3N4 was synthesized by calcinating. In the 2nd step, 7Ag-ZnO/S-g-C3N4 heterostructure photocatalyst was formed by in situ formation of 7Ag-ZnO NPs in the presence of different contents of S-g-C3N4 (3.5–75 wt%) through hydrothermal route. As a result of 7Ag-ZnO/S-g-C3N4 heterostructure, a large number of catalytic active sites were generated for photocatalytic degradation. Interestingly, the 7% Ag-ZnO nanoparticles (NPs) with 25% S-g-C3N4 exhibited 97% MB degraded within 40 min, which was degraded up to 57% by 7Ag-ZnO alone. Moreover, the photo corrosion of ZnO NPs was inhibited by doping with Ag and coupling with S-g-C3N4.