Opposite effect of gas phase H2O2 on photocatalytic oxidation of acetone and benzene vapors

The effect of additions of gas phase H2O2 was measured for gas phase photocatalytic oxidation of organic vapors. Photocatalytic oxidation of benzene vapor over TiO2 in a flow reactor resulted in a quick catalyst deactivation. Additions of gas phase H2O2 into the reactor feed provided enhanced and sustained oxidation of benzene vapor. The increase of inlet H2O2 vapor concentration from 0 to about 1000 ppm led to the one order of magnitude growth of benzene vapor complete oxidation rate. The highest rate of 1.1 nmol/s was observed at C6H6 concentration 124 ppm and H2O2 concentration 1000 ppm. In the case of acetone vapor photocatalytic oxidation, the rate of complete oxidation in the flow reactor decreased with an increase of gas phase H2O2 inlet concentration. TiO2 Degussa P25 provided higher oxidation rate in the presence of H2O2 than pure anatase TiO2.