Low temperature selective catalytic reduction of NOx by ammonia over H-ZSM-5: an IR study

The IR study of the interaction of NO2 with ammonia-covered H-ZSM-5 zeolite shows a very fast reaction at room temperature between NO2 and adsorbed ammonium ions. An adsorbed NO2 species is also formed. In the presence of NO + NO2 mixture ammonium ions are completely rapidly decomposed at 300-373 K. These data suggest some speculations on the mechanism of the reduction of NOx by ammonia on H-ZSM-5 catalysts.