Photocatalytic degradation of tetracycline hydrochloride with g-C3N4/Ag/AgBr composites

Abstract

Graphite carbon nitride (g-C3N4), as a polymer semiconductor photocatalyst, is widely used in the treatment of photocatalytic environmental pollution. In this work, a Z-scheme g-C3N4/Ag/AgBr heterojunction photocatalyst was prepared based on the preparation of a g-C3N4-based heterojunction via in-situ loading through photoreduction method. The g-C3N4/Ag/AgBr composite showed an excellent photocatalytic performance in the degradation of tetracycline hydrochloride pollutants. Among the prepared samples, g-C3N4/Ag/AgBr-8% showed the best photocatalytic ability for the degradation of tetracycline hydrochloride, whose photocatalytic degradation kinetic constant was 0.02764 min−1, which was 9.8 times that of g-C3N4, 2.4 times that of AgBr, and 1.9 times that of Ag/AgBr. In the photocatalytic process, •O2– and •OH are main active oxygen species involved in the degradation of organic pollutants. The photocatalytic mechanism of g-C3N4/Ag/AgBr is mainly through the formation of Z-scheme heterojunctions, which not only effectively improves the separation efficiency of photogenerated electron-hole pairs, but also maintains the oxidation and reduction capability of AgBr and g-C3N4, respectively.