Zinc oxide-supported silica gel (ZnO–SiO₂) as a sun light-driven photocatalyst

Band alignment and stability are important factors in the design of novel photocatalysts. Nonetheless, the wide band gap of metal oxides such as ZnO remains a bottleneck that constrains their broad use. In this study, we used the semiconducting nature of ZnO and the high surface porosity of silica to design a novel photocatalyst for incipient wetness impregnation. The doping effect of ZnO was determined using MOTT Shotkey analysis to obtain a clear image of the band structure and the fermi level position. The structural assets of the photocatalyst were studied using X-ray diffraction, scanning electron microscopy, and nitrogen isotherm. ZnO supported onto silica gel showed superior activity compared with ZnO. This efficiency is attributed to the presence of distinct types of pores vacillating from large wide pores to a smaller pores system as well as to the tapering of the band gap that allows the release of oxygen species. DFT calculations confirm that the fermi level of ZnO-SiO₂ has a higher electron density near the fermi level than ZnO, which is consistent with the experimental validation.