BILAYER FILM CATALYSIS OF ZnO-CdO AND A COMPARISON WITH ZnO FILM CATALYSIS

by PERIASAMY VAIRAVANATHAN, PONRAJESH

In this study, the photocatalytic activities of two semiconductor films were investigated: a bilayer film of ZnO-CdO and a unilayer film of ZnO. Both films were prepared by the chemical bath deposition (CBD) technique. The Tauc plot for the bilayer film supported that the film had a bilayer structure, since the bandgap of both CdO and ZnO were observed in the Tauc plot. The degradation of methylene blue was used as a measure of photoactivity. The reaction parameters studied include residence time in the flow reactor, liquid level in the batch reactor, and light source. In all experiments, the bilayer ZnO-CdO film showed higher photocatalytic activity than the ZnO film. Most importantly, the bilayer film was photoactive under visible light. This result demonstrates that bilayer film structure with two different semiconductors can be used to create novel photocatalytic films that are active in visible light.