Substitution of V5+ in BiVO4 with Ni2+ and the Improved Photocatalytic Degradation of Crystal Violet Under White LED Light Irradiation

The effects of the substitution of V⁵⁺ with Ni²⁺ at the corresponding sites in BiVO₄ on the crystal structures, optical properties, and photocatalytic efficiency of BiVO₄ was investigated. Ni²⁺ cations doped at the V⁵⁺ sites in BiVO₄ was confirmed by X-ray diffraction, Raman, X-ray photoelectron spectroscopy, ultraviolet–visible diffuse reflectance spectra, and photoluminescence spectra. Ni-doped BiVO₄ exhibited excellent degradation of crystal violet (CV) compared with the bare BiVO₄. For optimal Ni²⁺ doping of 5%, the degradation rate of CV, which reached about 95% within 180 min of LED light irradiation, was obtained. Ni doping can introduce advantageous defect states that significantly increase the separation and diffusion efficiency of the photo-induced charge carriers, thereby boosting the photocatalytic activity of crystal structures.