Fabrication of a novel Ag/AgCl/NH2-MIL-53(Fe) heterojunction photocatalyst for enhanced visible-light photocatalytic degradation of rhodamine B and tetracycline: performance and mechanistic investigation

Dyes and antibiotics possess high stability and are resistant to microbial degradation, leading to their persistence in the natural environment. Photocatalysis is an effective and green degradation method. In this work, a novel Ag/AgCl/NH 2 -MIL-53(Fe) (AAF) heterojunction photocatalyst was prepared using a solvothermal method, precipitation method, and photochemical reduction method, which effectively promotes the separation of photogenerated charge carriers. The study shows that the composite consisting of 95 wt% Ag/AgCl/NH 2 -MIL-53(Fe) (AAF-95) can photocatalytically degrade 99.4% of RhB within 15 min and 82.4% of TC within 12 min, achieving higher photocatalytic degradation activity than the individual materials. The main active species involved in the degradation are h + and •O 2 - . Based on Mott-Schottky tests, radical trapping experiments, and UV-vis DRS, a possible photocatalytic degradation mechanism and the advantages are proposed: AAF-95 broadens the light absorption range, and the NH 2 -MIL-53(Fe) increases the specific surface area, thereby enhancing the catalytic reaction activity. The coupling between the heterojunction and the SPR effect promotes the separation of photogenerated charge carriers and lowers the catalytic reaction barrier. These are the reasons for the enhanced photocatalytic degradation capability of the composite.