Novel Lu-doped Bi2WO6 nanosheets: Synthesis, growth mechanisms and enhanced photocatalytic activity under UV-light irradiation

Polycrystalline systems of lutetium doped bismuth tungstates Bi2WO6: Lu (Lu at% 0, 2, 5 and 8) were synthesized using the coprecipitation method, followed by thermal treatment at 500 °C. The Bi2WO6:Lu samples were characterized by X-Ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-Ray analysis (EDS) and UV-vis diffuse reflectance spectra (DRS). The XRD and SEM analyses showed that the as-prepared samples crystallized in the same orthorhombic structure and consist of agglomerated nanosheets. To characterize the photocatalytic activities, UV-visible spectrometry was used to analyze the evolution of Rhodamine B photodegradation in presence of the Bi2WO6: Lu photocatalysts. The characteristic absorption band of Rhodamine B at 554 nm shifted to lower wavelengths under UV irradiation. The pure Bi2WO6 and the 5% Lu doped Bi2WO6 photocatalysts presented the lowest and highest efficiencies, respectively. An interpretation of improved photocatalytic efficiencies was proposed.