Preparation of La-doped Bi2WO6 with rich oxygen vacancies and enhanced photocatalytic performance for removal of Rhodamine B

Abstract

• > La doped Bi 2 WO 6 with rich oxygen vacancies was prepared. • > The separation rate of photo-generated carriers is largely enhanced. • > The level of •O 2 - is significantly boosted. • > La-Bi 2 WO 6 exhibits higher activity than the reference Bi 2 WO 6 . To ameliorate the photocatalytic performance of Bi 2 WO 6 , La-doped Bi 2 WO 6 photocatalysts were prepared by a hydrothermal method using glacial acetic acid as solvent. The samples were carefully characterized by serval analytic methods. X ray photoelectron spectroscopy (XPS) and low-temperature electron spin-resonance (ESR) spectroscopy demonstrate that La-doped Bi 2 WO 6 photocatalysts have rich oxygen vacancies (OVs). Elemental mapping and XPS confirm the existence of La in Bi 2 WO 6 . Doping La into Bi 2 WO 6 significantly boosts the level of OVs, separation of photoinduced carriers and the generation of superoxide radical (•O 2 - ). Photocatalytic performance of the samples was evaluated by removal of Rhodamine B (RhB) under simulated sunlight irradiation. The results indicate that the activity of La-Bi 2 WO 6 is higher than the reference Bi 2 WO 6 . When the content of La is 0.6%, the degradation rate constant of RhB on the 0.6% La-Bi 2 WO 6 is 1.83 times of that of the blank Bi 2 WO 6 . Doping La into Bi 2 WO 6 is a reliable approach to promote the photocatalytic activity of Bi 2 WO 6 .