Visible light-induced degradation of tetracycline using CaFe2O4/CuWO4 composite and its mechanistic insights

Abstract

Water is an essential component for all life on earth, and the presence of antibiotics in water poses a potential threat to the environment. In this study, we report the synthesis of a CaFe₂O₄/CuWO₄ composite photocatalyst that can be activated by visible light using a two-step process. This involved hydrothermal treatment followed by sol-gel combustion. The morphological structure, element composition, photoelectric response, and other properties of the synthesized catalyst were thoroughly examined using various techniques, including XRD, TEM, XPS, PL, and EIS. Tetracycline (TC) was selected as a test antibiotic to evaluate the photocatalytic efficiency of the composite catalyst. The CaFe₂O₄/CuWO₄ composite exhibited 2.12 and 9.76-fold higher TC degradation efficiency compared to that of individual CaFe₂O₄ and CuWO₄, respectively, during 210 min of visible light exposure. The matched band positions of CaFe₂O₄ and CuWO₄ play a crucial role in enhancing photocatalytic activity by effectively separating and transferring light-induced carriers. O₂^-•, e^-, and OH^• were found to be the primary reactive species driving the process, and a plausible TC degradation mechanism was proposed. The composite catalyst demonstrated high stability and excellent recyclability. The findings have implications for understanding the mechanistic insights into visible light-enhanced photocatalysts for the degradation of water-borne organic pollutants.