Study on photocatalytic degradation of gaseous dichloromethane using pure and iron ion-doped TiO_2 prepared by the sol-gel methodZ

摘要

The synthesis of TiO_2 and Fe-TiO_2 by sol-gel method is demonstrated and characterized. The characterization of TiO_2 and Fe-TiO_2 is performed with instruments, including TGA/DTA, FTIR, UV-Vis, N_2 adsorption and SEM. Dichloromethane is used for the photocatalytic activity test. From the results of dichloromethane photocatalyitc degradation, the calcined temperature of TiO_2 and the presence of water vapor influence the photocatalytic activity. The optimum doping amount of iron ions is 0.005 mol%, and this can enhance the photocatalytic activity, while too great an amount will make the iron ions become recombination centers for the electron-hole pairs and reduce the photocatalytic activity. UV-Vis diffuse reflectance spectra of Fe-TiO_2 show an increase in absorbency in the visible light region with the increase in iron ions doping concentration The intermediate of dichloromethane photodegradation includes CHCl_3, CCl_4, CH_2Cl_2 and COCl_2. The presence of iron ions may reduce the adsorption of Cl element on the surface of the photocatalyst.