Efect of H2O on NO Reduction over NSR Catalyst 12CaO-7Al2O3/10%K

A novel NOx storage/reduction catalyst 12CaO-7Al2O3/10%K, defined as C12A7/K, was prepared, which possesses good NOx storage/reduction ability with a high sulfur-tolerance. The effect of H2O on the NO reduction features over the C12A7/K catalyst was investigated. The NO conversion and the N2 selectivity were measured as a function of temperature and H2O concentration. In the presence of 1.2% H2O, both the NO conversion and the N2 selectivity significantly decrease at lower temperature region (<500 ±C). At temperatures over 500 ±C, however, the NO reduction is only slightly influenced by H2O. The species of NO3?/NO2? are confirmed as main storage components in the C12A7/K catalyst, which are further reduced into N2 by H2 under the reduction conditions.