Effect of water vapor on microwave-assisted photocatalytic oxidation of organic pollutants over titania

It is known that the competitive adsorption of water vapor onto photocataly st causes a negative effect on gas-solid photocatalytic reaction. In this p aper, the effect of water vapor on the microwave-assisted photocatalytic ox idation of C2H4 and C2HCl3, with which as model organic pollutants, was exa mined under different reaction conditions. The results showed that H2O was an important factor to the photocatalytic oxidation. Because polarization o f different substances is quite different in microwave field, the energy of microwave was mostly absorbed by H2O for the photocatalytic reaction with water vapor. The improvement of C2H4 photocatalytic reactivity was attribut ed to desorption of water vapor from the catalyst surface in microwave fiel d. However, the result of C2HCl3 oxidation was opposite, where H2O was requ ired to complete the reaction.