Constructing an S-Scheme Znsno3-Cubi2o4 Heterojunction Through Interfacial Modulation to Boost Visible-Light-Induced Photothermal-Photocatalytic Degradation of Tetracycline

Abstract

Through the interface regulation of surfactant, using the hydrothermal method to deposit 0D ZnSnO3 on the surface of 3D CuBi2O4, the S-scheme ZnSnO3-CuBi2O4 (ZSCB) heterojunction photocatalyst was synthesized, which exhibits outstanding redox capabilities. The strong light absorption performance of CBO in the visible range promotes its excellent photothermal conversion ability under visible light. Under visible light irradiation, its surface temperature can be increased from 26.2℃ to 98.5℃ within 9 minutes. Images at 808 nm near-infrared radiation show that the S-scheme ZSCB heterojunction can convert 34.16% of light energy into heat energy in aqueous solution. Due to the S-scheme charge transport mechanism and photothermal effect of ZSCB, the heterojunction had excellent photogenerated carrier separation efficiency and high redox capacity, which can degrade 85.4% of TC within 90 minutes, and the degradation rate was 3.1 times that of monomer CBO, also excellent TC degradation performance in simulated natural water and different ionic. The Fukui index and the change of mass charge ratio of TC during the degradation process, predicting the attack site of TC at the atomic level and clarifying that the S-scheme ZSCB heterojunction was controlled by electrophilicity, nucleophile and free radical during the photothermal photocatalytic degradation of TC. The ecological structural activity relationship model and mung bean culture experiment revealed the low ecological risk of TC degradation from theory to practice. This study provides a novel approach to the degradation of emerging pollutants and the environmental toxicology research associated with S-scheme heterojunctions.

Keywords: ZnSnO3, CuBi2O4, S-scheme, Tetracycline, Photothermal effect, ecological risk.