Enhanced photocatalytic activity of highly porous ZnO thin films prepared by sol–gel process

Highly photoactive porous ZnO thin films on glass substrate have been prepared by a sol–gel process using Zn-acetate after sintering at 400 °C temperature. The films consist of spongy particle aggregates with uniform pores at the surface. Structural features and surface morphology were studied by XRD and SEM analyses. These films have been found to decompose aqueous solutions of phenol, chlorophenol, naphthalene and anthracene to CO2 quite efficiently. Concentrations decreased linearly with illumination time, and high rate constants were obtained for the degradation of these organics. The pH values of the solution changed with the irradiation time due to the formation of hydroxylated intermediate photoproducts which have been detected in many cases.