Photocatalytic Selectivities of Ethane, Methane and Dimethylether Controlled by Reaction Conditions and TiO2 Structure in the Degradation of Acetic Acid

The impact of photon flux, humidity and residence time using TiO2 P25 and of the surface area of a series of CristalActiv PC TiO2 anatase, on the selectivities of products formed in the continuous photocatalytic degradation of gaseous acetic acid (AA) on the scale of a few hundred ppm, in the presence or absence of O-2,O- was investigated. Under a continuous flow of air HCHO and C2H6 were the most important products detected. CH3OH was also formed but to a lesser extent. Under a continuous flow of N-2, the formation of these three products decreases whereas CH3OCH3, an interesting product which can be used as alternative fuel and CH4, is yielded. The impact of the experimental conditions on product formation, taking into account the intermediate formation of H2O2 and the favorable impact of the surface area on the formation of CH4 in the absence of oxygen and its opposite effect on the formation of C2H6 in the presence of air, was discussed.The presence of rutile phase in TiO2 P25 was also highlighted.