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

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, ^•O^2– 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.