PHOTOCATALYTIC EFFICIENCY OF ZnO FILMS PREPARED BY SOL-GEL METHOD USING COMPLEXATING AGENT OR POLYMER ADDITIVE

Thin ZnO films have been successfully prepared on glass substrates by the sol-gel method using two different solutions of zinc acetate with complexating agent (monoethanolamine, MEA) or polymer additive (polyvinyl alcohol, PVA). The films have been characterised by means of X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and UV-Vis spectroscopy. The films prepared by the complexating agent solution possess many separate ganglia on the surface, while the polymer modified solutions lead to the formation of some ganglia aggregates. The films morphology has significant influence on the photocatalytic properties. The higher photocatalytic activity and the faster degradation of the organic dye (94% degree of conversion after 3 h under illumination) over the ZnO samples obtained from complexating agent solution could be attributed to the greater number of active sites on the surface, while the polymer solution leads to aggregation of the ganglia. This results in a lower photocatalytic activity in the reaction of degradation of model waste water pollutant Malachite Green dye.