Enhancement of photocatalytic activity of BiVO₄ by barium doping

BiVO₄ has been successfully synthesized by solid state method and doped by barium in the sites of bismuth in 3%, 6%, 9% and 15% to form Bi_1-xBa_xVO₄ (x = 0.03, 0.06, 0.09 & 0.15). The products have been characterized using powder X-ray diffraction, diffuse reflectance spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and photoluminescence spectroscopy. The band gap of undoped BiVO₄ is calculated to be 2.19 eV and the barium doped BiVO₄ compounds exhibit band gaps which are closer to the band gap of undoped compound. The photocatalytic activities of undoped and doped catalysts for the degradation of methylene blue have been studied using UV-visible spectroscopy and found to be depended largely on the barium content and the particle size of the compounds. (author)