NSR催化剂12CaO-7Al2O3/10%K中水对NO还原性能的影响

主要讨论在不同反应温度和不同水蒸汽浓度下,新型的NOx储存-还原催化剂12CaO·7Al2O3／10％K(简称C12A7／K)中水的存在对NO还原性能的影响．研究结果表明,当存在1．2％水蒸汽,并低于500℃时,NO转化率和N2的选择性均降低,水蒸汽的存在对催化剂低温区的活性起到较明显的抑制作用;而温度高于500℃时,此抑制作用则基本消失,说明此时C12A7／K催化剂的水热稳定性较好．FT-IR结果证明储存NOx后的C12A7／K样品小形成了NO3／NO2的反应中间物种,用H2还原则可消除中间物种,以N2等形式放出。

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.