As a semiconductor, zinc oxide (ZnO) has better UV absorbing properties compared to other semiconductor materials, and therefore, it has better dye degrading abilities. However, ZnO tends to agglomerate, which lead to poor degradation compared to the other semiconductors. In this study, to overcome the agglomeration of ZnO, silica (SiO2) was combined with ZnO. The composite was tested for its photocatalytic activity. The ZnO/SiO2 photocatalyst was fabricated on a glass plate. In order to investigate the addition of SiO2 on ZnO, X-ray diffraction (XRD) and scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS) was used. The result of the XRD analysis demonstrates similar peak results with ZnO XRD data from ICSD 157132 with a hexagonal structure. The results indicate that the ZnO structure did not change after the addition of SiO2, while SEM-EDS results showed that SiO2 was supported on ZnO with 8% composition. The optimal composition was found to be ZnO/SiO2 95/5, as indicated by high degradation activity, which can degrade up to 89% methylene blue.
Part of the book: Visible-Light Photocatalysis of Carbon-Based Materials