Study on Energy Storage Ability of ZnO/TiO2 for Photocatalytic Degradation of Isopropanol

Abstract

The photocatalytic degradation of isopropanol under UV irradiation was studied by using p-n junction of ZnO/TiO2 photocatalysts prepared by sol-gel technique. Their energy storage ability was tested with their photocatalytic activity where there was no UV illumination. That was investigated by illumination the system with UV light for 2 h and off for 2 h until 8 h. The composition and surface structure of the catalyst were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), surface area analysis, and particle size analysis. The change in the isopropanol concentration was observed by using gas chromatography. The result showed that the degradation efficiency of the ZnO doped on TiO2 layer films was higher than the single-TiO2 thin film, about 74.0% and 48.0%, respectively. Moreover, acetone was found during the photocatalytic degradation process of isopropanol. The effects of isopropanol solution pH, ZnO loading, and ZnO calcination temperature were studied. ZnO calcined at 600ºC and 15 mol% at unadjusted pH was suitable for both photocatalytic activity and energy storage. The photocatalytic degradation rates of isopropanol for the first and second illumination were about 21.0% and 20.8%, respectively. With no illumination, the highest degradation of isopropanol was about 14.8%.