Preparation of Transparent ZIF-8/TiO2 Nanocomposite Thin Films for Photocatalytic Applications

Abstract

Transparent ZIF-8/TiO2 nanocomposite thin films were prepared by a two-stage dipcoating method. TiO2 was first deposited on glass substrates by sol-gel dip-coating. Heat treatment temperature, number of layers, and doping metal type or level were optimized in the first step. In the next step, ZIF-8 was grown by solvent-based crystallization method on TiO2 layers. Cu, Ce, Fe, or Zn-doped TiO2 thin films were prepared in order to increase the photocatalytic performance of the ZIF-8/TiO2 nanocomposite. The highest photocatalytic methylene blue degradation activities were obtained with the ZIF-8/TiO2 nanocomposite thin films prepared by using 1% Cu or 1% Ce-doped TiO2 thin films as the substrates. Both films exhibited 19% dye removal in 1 hour under 254 nm LED light irradiation, whereas the dye removal efficiencies were 36% and 29% , respectively, in 1 hour under 365 nm LED light irradiation.