Ultrasonic synthesis and characterization of mesoporous monoclinic BiVO4 nanopowder

Abstract

The BiVO4 sample was successfully synthesized from a mixture of ammonium vanadate, bismuth(III) nitrate, and nitric acid exposed to ultrasound irradiation. Structure, microstructure and optical properties of the obtained BiVO4 nanopowder were investigated. X-ray diffraction (XRD) analysis confirmed single phase monoclinic lattice system with average crystallite size of 50 nm in diameter. Scanning electron microscopy (SEM) micrographs revealed the tendency of crystallites to agglomerate forming larger irregular sub-micron spheres. Brunauer-Emmett-Teller (BET) method was used to estimate the specific surface area of the sample and determine pore shape and size. UV–vis spectroscopy measurements have revealed favorably high absorbance of the visible light with the calculated band-gap value of 2.48 eV. Calculated values of valence and conducting band energies are +2.77 eV and +0.29 eV respectively, suggested that BiVO4 can be used for photocatalytic degradation under sunlight irradiation as evident from the UV–vis spectrum.