Facile in situ construction strategy to deposit Mn0.5Cd0.5S nanoparticles on TiO2 nanosheets for highly efficient visible light photocatalytic degradation of tetracycline

Abstract

Developing a highly efficient visible-light-driven TiO₂-based photocatalyst for the degradation of tetracycline remains challenging due to the high photogenerated electron/hole recombination rate and narrow visible light response range of TiO₂. To address these problems, novel heterojunctions are fabricated by coupling TiO₂ nanosheets with Mn_0.5Cd_0.5S nanoparticles as visible-light photocatalysts. The as-synthesized photocatalysts exhibit high photogenerated electron/hole separation efficiency and enhanced visible-light absorption due to the well-matched energy levels, leading to the highly efficient degradation of tetracycline under visible light irradiation and excellent recyclability. The degradation efficiency of the optimum MCS/TiO₂-II photocatalyst could reach 90% within 120 min, which was about 2.5 times and 6.9 times higher than those of MCS and TiO₂, respectively. Furthermore, the degradation mechanism of tetracycline was revealed in depth based on the trapping experiments, XPS, photoelectrochemical characterizations, and DFT calculations. Therefore, this work provides an effective approach to explore excellent photocatalysts to realize the highly efficient removal of refractory tetracycline under visible light.