Rational design and construction of S-scheme CeO2/AgCl heterojunction with enhanced photocatalytic performance for tetracycline degradation

Abstract

Semiconductor-based photocatalysis has attracted extensive attentions in waste water treatment and environment remediation. However, a single semiconductor photocatalyst inevitably encounters a dilemma between light absorption and redox ability of photoinduced holes and electrons. In this work, an S-scheme CeO2/AgCl heterojunction photocatalyst was designed, prepared and characterized by various techniques. The as-prepared CeO2/AgCl composite photocatalyst exhibited enhanced photocatalytic activity compared with single CeO2 and AgCl as revealed by the photodegradation of tetracycline (TC), a widely used antibiotic. According to UV–Vis spectral changes and degradation mass spectra of TC, the CeO2/AgCl composite photocatalyst not only can destroy the B, C, D rings, but also the A ring of TC, which cannot be destroyed by most of previously reported photocatalysts. The enhanced photocatalytic ability of CeO2/AgCl composite was due to the formation of an S-scheme heterojunction structure between CeO2 and AgCl, which simultaneously retained the maximum redox ability of photoinduced holes and electrons in the valence band of AgCl and in the conduction band of CeO2, respectively, resulting in the production of highly efficient O2−, OH and h+. This work provided insight into the rational design and construction of S-scheme heterojunction composites and new possibility of photocatalytic degradation of antibiotic wastewater.