Effect of titanium dopant on the surface features and on the photocatalytic characteristics of ZnO films

The crystallographic phase, surface features and photocatalytic properties in the reaction of decolorization of Malachite Green dye over TiO2 (0–100 mol%) doped ZnO films have been investigated. The films have been prepared by polymer modified spray pyrolysis. The crystallization degree and the size of the crystallites comprising the films have been found to be influenced by the TiO2 content in the spraying solution. The undoped ZnO film has little porosity. The titania dopant causes formation of hexagonal nanorods on the ZnO surface. The increase in TiO2 content results in enhancement of both size and crystallization degree of the nanorods. When the TiO2 content is increased (i) the Zn2p, O1s and Ti2p peaks are shifted to lower binding energies, (ii) the atomic ratio of OL/Zn is decreased and (iii) the amount of adsorbed hydroxyl (OH−) species is increased. All the TiO2 doped ZnO films manifested higher photocatalytic activity than that of the undoped ZnO and TiO2 samples. The films obtained from solutions with 50 mol% TiO2 showed the fastest decoloration of the dye.