A novel all-solid-state Z-scheme BiVO4/Ag/Cu2O heterojunction: Photocatalytic and photothermal synergistic catalysis of tetracycline under simulated sunlight irradiation

The possible hazards posed by tetracycline (TC) to the environment and public health have made it a critical concern. In this work, the all-solid-state Z-scheme heterojunction BiVO4/Ag/Cu2O nanocomposites (NCs) were synthesized through a hydrothermal approach for the purpose of achieving efficient degradation towards TC. BiVO4/Ag/Cu2O NCs were able to efficiently degrade TC when exposed to simulated sunlight. The results showed that the photocatalytic efficiency was significantly influenced by Cu2O and Ag nanocrystals. The presence of Ag with large light absorption capability facilitated the efficient electron (e(-)) transfer between BiVO4 and Cu2O nanocrystals, thereby expanding the spectral range of light absorption in BiVO4/Cu2O NCs. Under photocatalytic and photothermal synergistic conditions, BiVO4/Ag/Cu2O NCs with an optimal addition of Ag were able to degrade TC within 60 min at reaction rate constant (k) of 0.04816 min(-1). It was discovered that the best-performing photocatalysts (BAC-2) achieved photothermal conversion rates as high as 27.9 %, and they could exhibit outstanding photocatalytic and photothermal efficiency even after six cycles. Furthermore, the results obtained in radical trapping experiments suggested that photogenerated holes (h(+)), electrons (e(-)), superoxide radicals (center dot O-2(-)), hydroxyl radicals (center dot OH) and singlet oxygen (O-1(2)) were involved in the photocatalytic degradation of TC. In the context of practical application, the effects of different initial TC concentrations and different irradiation conditions were studied in depth. In addition, the all-solid-state Z-scheme heterojunction mechanism for degrading TC was put forward. This research endeavors to broaden the application scope of all-solid-state Z-scheme heterojunction photocatalysts, with the aim of achieving significantly improved photocatalytic degradation of antibiotic pollutants.