Effects of reaction temperature on the photocatalytic activity of photo-SCR of NO with NH3 over a TiO2 photocatalyst

Effects of reaction temperature on the activity of photo-assisted selective catalytic reduction (photo-SCR) of NO with NH3 were investigated under very high GHSV conditions (100 000 h(-1)). The reaction temperature had a significant effect on the photo-SCR activity over a TiO2 photocatalyst. Maximum NO conversion was achieved at 433 K (NO conversion = 84%, N2 selectivity = 100%). The apparent activation energies in the low and high temperature range were evaluated to be 9.0 kJ mol(-1) (353-433 K) and -2.7 kJ mol(-1) (493-593 K), respectively. Kinetic analysis revealed that the rate-determining step in the photo-SCR was decomposition of NH2NO intermediates in all the ranges of the reaction temperature (353-593 K). The reaction temperature affects not only the rate constant of decomposition of NH2NO intermediates but also the total number of active sites ([S](0)) and the equilibrium constant of NH3 adsorption, resulting in the dynamic change in the reaction rate.