Effect of lanthanum doping on structural, optical, and photocatalytic properties of YVO4

In this study, we report the solid-state reaction synthesis of yttrium vanadate (YVO4)-based undoped and lanthanum (La)-doped powders. The photocatalytic performances, structural, morphological, and optical analyzes are presented. The X-ray diffraction analysis of samples indicates the crystalline tetragonal type crystal structure of YVO4 and no other lanthanum related impurity and/or secondary phases were detected. Photoluminescence analysis of samples show combined white light emission peaks that appeared at 478, 571 and 613 nm. To examine the photocatalytic activities, the degradation of methylene blue (MB) dye was monitored in the presence of these photocatalysts under the ultraviolet light irradiation. Pseudo-first-order reaction rate constant (k) of YVO4:La3+ (0.00846 min(-1)) is determined 66% greater than undoped one (0.00287 min(-1)). These results are compatible with the absorption spectra, as the energy band gap of the undoped photocatalyst was 3.8 eV while that of the doped one decreased to 3.54 eV.