Construction of Sn-Bi-MOF/Ti3C2 Schottky junction for photocatalysis of tetracycline: Performance and degradation mechanism

In this study, Sn–Bi–MOF/Ti3C2 heterojunction catalysts were prepared using the solvothermal method, and their photocatalytic ability to degrade and mineralize tetracycline (TC) under illumination was investigated. After 90 min of photocatalysis, the pollutant had a degradation efficiency of 96.2% and a mineralization rate of 45.5%. The physicochemical properties of the catalysts were analyzed using various methods. The effects of the solution pH, coexisting anions, and water quality on the catalyst performance were investigated. ·O2− and h+ are the main active substances in the photocatalytic mechanism, as demonstrated by free-radical quenching experiments and EPR tests. The degradation of TC and the intermediates produced were determined using 3D fluorescence and LC-MS. The photocatalytic mechanism of Sn–Bi–MOF/Ti3C2 was proposed based on free radical determination and electrochemical tests. The formation of the Schottky junction accelerated the transfer of electrons to Ti3C2 and improved the separation of charges, which led to the generation of free radicals. Sn–Bi–MOF/Ti3C2 still exhibited good catalytic ability after four cycles of the experiments, and the XRD patterns before and after the reaction were consistent, which illustrates that the composite structure was stable. Overall, Sn–Bi–MOF/Ti3C2 has promising applications in the photocatalytic removal of refractory pollutants.