Synthesis and characterization of TiO2 and Ag/TiO2 thin-film photocatalysts and their efficiency in the photocatalytic degradation kinetics of Orange G dyestuff

The TiO2 and Ag/TiO2 solutions were prepared by the sol–gel method. The solutions were coated on the quartz tubes by using the dip-coating method. The produced TiO2 and Ag/TiO2 thin-film photocatalysts were characterized by using scanning electron microscopy–energy-dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and chronoamperomet- ric measurements. The characterization results showed that the photocatalysts were successfully synthesized, and the Ag/TiO2 thin-film photocatalyst had a higher photocurrent intensity than the TiO2 thin-film photocatalyst. To eliminate the lack of literature in the kinetic study, the synthesized photocatalysts were examined on the degradation of the Orange G solution. The effects of initial dye concentration, temperature, and light intensity on the photocatalytic degradation kinetics of Orange G were investigated. The network kinetic model was applied to determine the appropriate kinetic model for the decomposition of Orange G with the produced photocatalysts. The network kinetic model was found to be the appropriate kinetic model for the degradation of Orange G using the TiO2 and Ag/TiO2 thin film photocatalysts. The calculated activation energies of the TiO2 and Ag/TiO2 thin film photocatalysts by using the result of the experiments are 20.02 and 16.16 kJ/mol, respectively. Besides, the general rate equations for each photocatalyst were specified.