Preparation and Characterization of NiO-WO3 nanocomposite with Enhanced Photocatalytic Activity under Visible Light Irradiation

NiO/WO3 nanocomposites has been successfully synthesized by a precipitation deposition method with different mole ratios were synthesized and characterized by Fourier transform infrared Spectra (FT-IR), X-ray diffraction (XRD), Energy dispersive X-ray spectroscopy (EDX), Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) techniques. Absorption range and band gap energy, which are responsible for the observed photocatalyst behavior, were investigated by UV-vis diffuse reflectance spectroscopy (UV-vis-DRS). The formation of cubic structured NiO and orthorhombic structured WO3 was confirmed by powder X-ray diffraction analysis. The photocatalytic activity was tested for the degradation of Crystal Violet (CV) under visible-light irradiation. It was found that 0.5-0.5 mole NiO-WO3 displayed excellent photocatalytic activity than that of 0.6-0.4 mole NiO-WO3, 0.4-0.6 mole NiO-WO3. The effect of operation parameters such as initial dye concentration, pH and catalyst concentration has been investigated in detail. The mechanisms of the enhancement of photocatalytic activity of the nanocomposite photocatalyst will be discussed by the p-n heterojunction principle and the valence band theory. The pure nanocomposite systems have been also reported for a comparative purpose.