Facile fabrication for BiPO 4 /brookite TiO 2 heterojunction for enhanced photocatalytic activity under visible-light irradiation

In this study, high-purity rice-shaped brookite TiO 2 nanoparticles with a high specific surface area were synthesized via a simple hydrothermal method. The brookite TiO 2 nanoparticles exhibited a rice-like morphology with smooth surfaces and tapered ends. Subsequently, it was employed to fabricate BiPO 4 modified brookite TiO 2 composites to improve the photocatalytic activity. The samples were characterized by XRD, SEM, TEM, XPS and DRS. The results revealed that BiPO 4 particles dispersed on the surface of brookite TiO 2 , forming an intimate heterostructure. Compared with pure-phase brookite TiO 2 , the BiPO 4 /brookite TiO 2 composites exhibited enhanced photocatalytic activity under visible light irradiation. The improvement in photocatalytic performance originated from the formation of a BiPO 4 /brookite TiO 2 heterojunction, which effectively facilitated the separation efficiency of photogenerated electron-hole pairs. In addition, based on free radical trapping experiments, not only were the effective active species responsible for the photocatalytic degradation of ofloxacin (OFX) identified, but the mechanism of pollutant degradation by the BiPO 4 /brookite TiO 2 heterojunction composite was also elucidated.