Preparation and application of Bi4O7/Cu-BiOCl heterojunction photocatalyst for photocatalytic degradation of tetracycline under visible light

The construction of heterojunction composites using suitable semiconductor materials is an effective method for the removal of organic pollutants from wastewater. Herein, Bi4O7/Cu-BiOCl nanocomposites were synthesized by hydrothermal and calcination methods as photocatalysts. The morphology, structure, and optical properties of the composites were characterized by SEM, XRD, EDX, FT-IR, DRS, and PL related techniques. Results show that Cu-BiOCl was tightly loaded on the surface of Bi4O7, and the heterojunction was successfully formed between them. The photocatalytic activity of the composites was evaluated by the degradation of tetracycline (TC) under visible light irradiation. It was found that Bi4O7/Cu-BiOCl-2 exhibit excellent photodegradation performance than that of single-phase materials, and the photodegradation efficiency of TC could reach 91% in short time (60 min). Meanwhile, Bi4O7/Cu-BiOCl-2 composite showed high stability and degradation efficiency in simulation experiments with different water sources and inorganic anions doping. The possible degradation pathways were investigated by LC-MS and 3D EEM, and the mechanism was studied using capture experiments and electron spin resonance. Thus, this work provides a new approach for the design of bismuth-based heterojunction photocatalysts.