Enhanced interfacial charge transfer and ROSs formation by oxygen vacancies-rich S-scheme heterojunction for efficient photocatalytic degradation of tetracycline in low-power LED light

Addressing such limitations of traditional photocatalysts as poor visible light absorption, substantial electron-hole recombination, and inefficient reactive oxygen species (ROS) generation is crucial. In this paper, oxygen vacancies (OVs) rich Bi 2 MoO 6 (BMO)/ZnSe S-scheme heterojunction was successfully prepared using a simple and mild solvothermal method. The introduction of OVs effectively shortened the band gap and increased the visible light absorption range. The mechanism of inducing OVs into BMO by adapting the concentration of surfactants was uncovered using both experimental and DFT simulation results. OVs-BMO/ZnSe exhibited an enhanced charge transfer capacity because OVs facilitated the formation of a rapid electron transfer pathway at the heterojunction interface. The synergistic effect of OVs and S-scheme heterojunction could effectively inhibit the recombination of photogenerated carriers. Its degradation efficiency and turnover frequency per wattage of light (TOF/P) reached 92.1% and 854.98 × 10 -10 (mol·g −1 ·J -1 ), respectively, during the low power LED white light-driven photocatalytic degradation of 50mg/L TC. The high value of TOF/P demonstrated its practical application potential in comparison with some other reported photocatalysts. Liquid Chromatography-Mass Spectrometry (LC-MS) characterization and ECOSAR simulation results indicated that OVs promoted the generation of ROS, in which ·O–2, 1 O 2 and h + significantly reduced the toxicity of intermediate products.