NO oxidation by simultaneous action of a dielectric
barrier discharge and TiO2 photocatalyst was investigated as a function
of the inlet gas composition (NO, O2, N2) and the input energy.
Concentrations of various NOx species and ozone in the outlet were
detected by the optical absorption spectroscopy. Higher content of O2
(10% and higher) increased the removal of NO and resulted in a higher
output of N2O5. TiO2 coating on a reactor electrode resulted
in the time-depending oxidation of NO. Initially the concentration of
untreated NO fell below the level achieved without TiO2 but after few
minutes the positive effect of TiO2 diminished. The initial decrease in
NO level due to the presence of TiO2 coating is explainable by surface
reactions of NO species and absorbed oxygen. After few minutes, the surface
states responsible for the initial removal of NO saturated and the effect of
TiO2 vanished.