Flower-like Bi <sub>2</sub> SiO <sub>5</sub> /Bi <sub>4</sub> MoO <sub>9</sub> heterostructures for enhanced photocatalytic degradation of ciprofloxacin
Chentao Zou, Mengjun Liang, Zhiyuan Yang, Xin Zhou, Yun Yang, Shuijin Yang
Abstract
Abstract Bi 2 SiO 5 /Bi 4 MoO 9 photocatalysts with heterostructures were successfully prepared using a one-pot solvothermal route. The effect of the molybdenum source on composite formation is discussed. Under ultraviolet light irradiation, the Bi 2 SiO 5 /Bi 4 MoO 9 heterojunction photocatalyst exhibited higher photocatalytic performance than Bi 2 SiO 5 and Bi 4 MoO 9 towards the degradation of ciprofloxacin (CIP). This dramatically enhanced photoactivity can be ascribed to the construction of a heterojunction interface between Bi 2 SiO 5 and Bi 4 MoO 9 , which not only suppresses the recombination of photoexcited charge carriers but also enhances light absorption. In addition, from a practical point of view, the the effect of initial CIP concentration and coexisting ions on the photodegradation process using as-prepared Bi 2 SiO 5 /Bi 4 MoO 9 heterojunction photocatalysts was explored. Trapping experiments demonstrate that photoexcited holes and superoxide radicals are the main active species in the photodegradation of CIP over Bi 2 SiO 5 /Bi 4 MoO 9 heterojunctions. Meanwhile, the conduction band and valence band potentials of Bi 2 SiO 5 and Bi 4 MoO 9 were measured by density functional theory calculation, diffuse reflectance spectroscopy and Mott–Schottky curves. A possible photocatalytic mechanism for CIP degradation over the Bi 2 SiO 5 /Bi 4 MoO 9 heterojunction is proposed.