A bilayer film of ZnO and TiO2 was preliminarily proven to be a possible photocatalyst to be catalytically active when there is no UV illumination. The catalyst was developed based on the principle of p-n junction with TiO2 as an n-type and ZnO as a p-type semiconductor. The sol-gel method was used to fabricate the bilayer film. The TiO2 film was first spin coated on a glass plate followed with the ZnO layer. The photocatalytic and energy storage properties were tested using acid orange 7 (AO7) as a model compound. Adsorption of AO7 was allowed before the start of the investigation. A UV light source was turned on for two hours before off for two hours, followed with another two-hour illumination and two-hour without illumination. Solution was taken at 2nd, 4th, 6th, and 8th hour of the experiment for qualitative analysis. Results showed that even though the TiO2 film can degrade AO7 with illumination illumination, its photocatalytic activity dropped to virtually zero without illumination. With the addition of ZnO, there was a significant increase in the film activity with illumination. Even more interesting is that the ZnO/TiO2 bilayer film was able to degrade AO7 when there was no illumination, implying that the film could store energy during illumination and exploit the energy when there was no illumination. During the investigated two cycles, the film activity with and without illumination only slightly dropped from its first cycle.

ZnO/TiO2 bilayer film: Energy storage and photocatalytic properties

251st National Meeting (2016)

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