Mechanistic study of B-TiO2/BiVO4 S-scheme heterojunction photocatalyst for tetracycline hydrochloride removal and H2 production

Abstract

S-schemed photocatalysts have been employed extensively to address energy issues and environmental contaminants because of their high redox ability and effective separation of photocharges. In this study, a novel S-scheme B-TiO2/BiVO4 photocatalyst was successfully fabricated using a simple in-situ hydrothermal method to enhance tetracycline hydrochloride (TCH) degradation and H2 evolution. The unique composition of B-TiO2 and BiVO4, as well as their synergistic effect, increased the number of multidimensional active reaction sites and enhanced the efficiency of photogenerated electron pair separation. In particular, when exposed to visible light, the rate of H2 evolution increased to 561.99 μmol·g−1·h−1, and the rate of TCH breakdown increased to 89.30 % in 120 min. The effects of initial pH, catalyst dosage, TCH concentration, and various coexisting anions were studied. It was discovered that pH and various anions had the greatest impact on the photocatalytic performance of B-TiO2/BiVO4 for the breakdown of TCH. In addition, free radical capture experiments and Electron paramagnetic resonance (EPR) revealed that ·O2− and h+ were the most important reactive species that accelerated the photocatalytic activities of B-TiO2/BiVO4. Work function calculations demonstrated that the presence of internal electric field (IEF) in the special B-TiO2/BiVO4 heterojunction, indicating the formation of an S-scheme heterojunction in the B-TiO2/BiVO4 system, which greatly facilitated the separation of electron-hole (e−-h+) pairs to promote efficient TCH degradation and hydrogen production. This study provides a potential strategy for developing high-performance photocatalysts that can produce clean energy without negatively impacting the environment.