Bi2WO6 doped with rare earth ions: Preparation, characterization and photocatalytic activity under simulated solar irradiation

Rare-earth modification Bi2WO6 composites (RE/Bi2WO6) were studied by experimental performance and theory computation based on the different 4f orbits of selected rare earth elements (La, Ce, Gd, and Yb). The prepared RE/Bi2WO6 was characterized by XRD, SEM/TEM, XPS, UV-vis DRS, and N2 adsorption to learn their physical-chemical properties. Azo dye Rhodamine B (RhB) was photodegraded as a target pollutant to investigate the photocatalytic activity of prepared RE/Bi2WO6 composites. The results of experiment and computation show that four rare earth elements with different electron configurations retain the phase and morphology of Bi2WO6 and enhance the removal efficiency of RhB under simulated solar irradiation. The optimum doping contents are 0.01%, 0.05%, 0.05% and 0.01% for La-, Ce-, Gd-, and Yb-doped Bi2WO6, respectively. However, light rare earth La and Ce doped composites indicate some difference in visible light adsorption capacity and mineralization on RhB compared with heavy rare earth Gd and Yb doped composites. Both La/Bi2WO6 and Ce/Bi2WO6 possess larger pore size and higher mineralization ability than Gd/Bi2WO6 and Yb/Bi2WO6 under the same experimental conditions while Gd/Bi2WO6 and Yb/Bi2WO6 show stronger red shift to the visible light due to the more 4f electrons. The hole oxidation plays a major role in the photodegradation of RhB by all RE/Bi2WO6.