Synthesis of Er-doped Bi2WO6 and enhancement in photocatalytic activity induced by visible light

Bi2WO6: Er3+ with hierarchical flower-like microstructures were synthesized by a one-step hydrothermal method. The photocatalysts thus obtained were characterized in detail by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), X-ray photoelectron spectroscopy (XPS) as well as photoluminescence (PL) measurements. Results obtained by XPS confirmed the presence of Er3+ dopants in Bi2WO6. Moreover, the results obtained from SEM have shown that doping with Er ions results in hierarchical flower-like microstructures of Bi2WO6. Under visible light irradiation, with an appropriate doping content, the photocatalysts exhibit significant improvement in the photocatalytic activity as the separation efficiency of the photogenerated electron-hole pairs is enhanced. Notably, the photocatalytic activity of 1.5% Bi2WO6: Er3+ is 3.69 times that of undoped Bi2WO6. The results indicate that an appropriate doping content can improve photocatalytic activity, caused by wider band gap, hierarchical flower-like microstructures, and defects generated by doping with Er3+, which in turn increase the separation efficiency of the photogenerated electron-hole pairs.