Construction of a Bi2WO6/TiO2 heterojunction and its photocatalytic degradation performance†
Abstract
TiO2 was prepared via a solvothermal method, and a Bi2WO6/TiO2 heterojunction was constructed via a hydrothermal method. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to analyze the crystal structure and morphology of composite photocatalysts with different molar ratios. X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectroscopy (EDS) were used to analyze the elemental composition and chemical state of the photocatalysts. We explored the degradation performance of the photocatalysts toward rhodamine B (RhB) and tetracycline (TC). When the molar ratio of TiO2 to Bi2WO6 is 6, the composite photocatalyst has the best degradation performance. Under visible light irradiation for 20 min and 25 min, the degradation rates of RhB and TC were 96% and 78%, respectively. The PL and photocurrent results show that the combination of TiO2 and Bi2WO6 can significantly improve the photogenerated carrier separation efficiency of the composite photocatalyst. The main active species in the photocatalytic degradation process is h+, as h+ can not only directly degrade pollutants, but also undergo redox reactions with OH− to generate ˙OH, which participates in the degradation of organic pollutants.