The preparation of S-SnO 2 /g-C 3 N 4 heterojunction and its photocatalytic degradation of phenol and trichlorophenol

A new S-SnO2/g-C3N4 heterostructure composite was prepared by a solution-ball milling-baking method in this study. The photodegradation efficiencies of phenol and trichlorophenol were experimentally studied at different pH values and H2O2 concentrations. XRD, XPS, UV–Vis DRS and Mott-Schottky were conducted to characterize the microstructure and test the photocatalytic performance of the materials. The photocatalysis mechanism of the S-SnO2/g-C3N4 composite was deeply explored by radical capture experiments. The results showed that some Sn4+ in the S-SnO2 was substituted by S6+, which reduced the band gap of SnO2 and formed a Type II charge transfer mechanism with CN. Thus, the photocatalytic activity of the S-SnO2/g-C3N4 composite was improved compared to SnO2 and g-C3N4 by promoting the separation of photogenic electrons from holes and facilitating the generation of ·O2− and h+.