In-situ immobilization of Ag/AgCl on sulfurized g-C3N4 nanosheet for enhancing visible-light driven photocatalysis toward simultaneous oxidation of tetracycline and reduction of Cr(VI) in water

The Ag/AgCl-S@CN photocatalyst was successfully prepared by in-situ formation of Ag/AgCl nanoparticles on the sulfurized g-C3N4 nanosheets. The catalytic activity of the photocatalyst was thoroughly explored by simultaneous photocatalytic oxidation of tetracycline (TC) and reduction of chromate, Cr(VI), under visible light. The results demonstrated that the photocatalytic composite could harvest visible light energy and facilitate charge separation efficiency due to the presence of abundant active sites, which ultimately enhanced the photocatalytic oxidation of TC and reduction of Cr(VI). The Z-scheme heterojunction, provided mainly h+ and O2•− for TC oxidation and e− for Cr(VI) reduction concurrently. Moreover, the photocatalyst enabled effective concurrent conversion of TC and Cr(VI) in a wide pH range. LC/MS-MS study of intermediates revealed the major TC photocatalytic breakdown routes, which included hydroxylation, oxidation, cleavage and demethylation. This study provides new perspectives into the approaches for the creation and application of Z-scheme heterojunction-based nanocomposites in the simultaneous removal of diverse hazardous contaminants from the environment. [Display omitted] •A Z-scheme Ag/AgCl-S@CN was successfully constructed.•Ag/AgCl-S@CN exhibited outstanding ability for the simultaneous removal of TC Cr(VI).•Hole (h+) and superoxide (O2•−) were the main reactive specie responsible for TC removal.•Ag/AgCl-S@CN was chemically stable during photocatalytic experiments.•Simultaneous photocatalytic removal of Cr(VI) and TC was achieved.