Optical, electrical and visible light-photocatalytic properties of yttrium-substituted BiVO4 nanoparticles

Yttrium-substituted (11.3 and 30.7 at.%) BiVO4 and pristine BiVO4 nanoparticles were synthesized by hydrothermal method. They were characterized by high resolution scanning electron, field emission scanning electron, transmission electron and high resolution transmission electron microscopies, powder X-ray diffraction, and energy dispersive X-ray, Raman, UV–vis diffuse reflectance, photoluminescence and solid state impedance spectroscopies. Y-substitution favors transformation of monoclinic phase of BiVO4 to tetragonal phase. High Y-substitution increases the crystallite size as well as the band gap energy and enhances charger carrier recombination. The charge transfer resistance of 11.3% Y-substituted BiVO4 is much less than those of the others. The visible light photocatalytic activity of 11.3% Y-substituted BiVO4 nanoparticles is larger than the rest. The larger photocatalytic activity of 11.3% Y-substituted BiVO4 nanoparticles has been explained in terms of mean crystallite size, recombination of photoformed electron–hole pairs and charge transfer resistance.