Selective removal of polar VOCs by novel photocatalytic activity of metals co-doped TiO2/PU under visible light

Abstract

In this study, Ag and V co-doped TiO2 deposited on polyurethane (Ag@V-TiO2/PU) was for novel photocatalytic removal of gaseous volatile organic compounds (VOCs). The combination of V doping, which enhanced internal electron transfer in the TiO2 lattice, and Ag doping, which exhibited high internal electron transfer in the Ag2O and enhanced exterior electron transfer among Ag particles, Ag2O and TiO2, increased the photocatalytic activity of Ag@V-TiO2/PU for the removal of VOCs in aerosol. The surface area of this co-doped photocatalyst was also higher than that of the undoped and single-dopant photocatalysts. The optimal combination of weight ratios of Ag/TiO2 and V/TiO2 for maximizing the surface area and photocatalytic activity of TiO2 was 4 and 2%, respectively. Under visible light, the removal efficiency of individual hexane and butyl acetate gas by 4Ag@2V-TiO2/PU was 93.7 and 95.5%, respectively. The removed hexane and butyl acetate were mineralized into CO2 with ratios of 93.2 and 96.2%, respectively. The individual removal of hexane and butyl acetate gas by Ag@V-TiO2/PU was similar; however, in the mixture stream of both VOCs, much more butyl acetate than hexane was photocatalytically removed. This was associated with the much higher polarity of butyl acetate than that of hexane, so that the photocatalyst surface, where most of the oxy radicals were generated to oxidize the VOCs, was more occupied or covered by butyl acetate than by hexane.