摘要
利用程序升温反应考察了 10 %H2 O存在时Cu Al MCM 4 1催化剂上的NO选择性还原反应 ,同时结合XRD ,N2 吸附等温线 ,NMR ,TPD和TPR等技术对催化剂的化学吸附性能和结构特征进行了表征 .活性测试结果表明 ,在含水气氛中进行NO选择性还原反应时催化剂的活性下降较小 ,且是可逆的 ,4 0 0℃时催化剂的活性可维持 30 0min以上 .通过多种表征可知 ,分子筛骨架未发生坍塌 ,催化剂活性变化的原因是H2 O的存在抑制了NO和C3 H6在催化剂活性位上的吸附 ,同时在反应过程中形成了一定量的CuO物种 。
The temperature-programmed reaction and characterization studies were performed over Cu-Al-MCM-41 to examine the effect of a high concentration of water vapor on the catalyst activity in the selective catalytic reduction of NO by C3H6. The presence of 10% water in the feed gas showed a minor inhibition on the activity of the catalyst. Under the dry conditions (0.1% NO, 0.1% C3H6, 2.0% O-2 and balanced with N-2), the No conversion of 37% was obtained at 370 degreesC. When the feed gas contained 10% water vapor, the maximum conversion of NO decreased to 34%. Under the dry and wet condition, the catalyst was stable for 300 min reaction at 400 degreesC. The characterization of the catalyst by using XRD, N-2 isothermal adsorption, NMR, TPR and TPD techniques revealed that the structure of Cu-Al-MCM-41 remained unchanged after reaction under the humidified atmosphere, implying that dealumination of the zeolite did not occur. The reason for the activity loss could be attributed both to the inhibition of water on the adsorption of C3H6 and NO on the active site, and to the formation of CuO during the reaction resulting in the decrease of the active site.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2002年第3期257-261,共5页
基金
"跨世纪优秀人才培养计划"基金项目
教育部重点科技项目(93 0 3 9)
