Titania/zinc oxide nanocomposite coatings on glass or quartz substrate for photocatalytic degradation of direct blue 71

Abstract

Zinc titanate nanocomposite was coated on glass and quartz substrate by sol–gel method. Powder X-ray diffraction (XRD) patterns of the nanocomposite coatings demonstrate that heat treatment change crystalline phase of zinc titanate nanocomposite. Higher temperature led to higher purity of the hexagonal zinc titanate phase. Scanning electron microscope/energy dispersive X-ray spectrometry (SEM/EDX) images demonstrate that size of the nanoparticles decreases with increasing of calcination temperature with an average grain size of 68nm. UV–vis diffuse reflectance spectra (DRS) of the nanocomposites show that the absorption edge of zinc titanate thin films is shifted to higher wavelengths at higher annealing temperatures which is probably due to the atomic inter diffusion between titania nanoparticles and zinc oxide. Photocatalytic activity of the nanocomposites toward photodegradation of direct blue 71 (DB71) was evaluated under UV visible light irradiation. The results indicate that hexagonal zinc titanate nanocomposite exhibit highest photocatalytic activity among the prepared samples.