Cu－Al－MCM－41的Si／Al比对贫燃条件下NO选择性催化还原的影响

 采用连续流动固定床石英反应器，在反应气体为0．1％NO，0．1％C3H6，2％O2，流量为500ml／min以及催化剂装量为0．1g的条件下，考察了Cu－Al－MCM－41的Si／Al比值对贫燃条件下NO选择性还原活性的影响．结果表明，当Cu交换度低于100％时，随Si／Al比值的增加，NO的最大转化率增加．TPD和TPR的研究结果表明，不同的Si／Al比值，改变了Cu在分子筛结构中的化学微环境，使活性中心Cu2＋的浓度和性质发生变化，从而影响其对NO的转化效率．

Effect of Si/Al Ratio in Cu-Al-MCM-41 on Selective Catalytic Reduction of NO under Lean Burn Conditions

Cu ion exchanged Al MCM 41 catalyst samples with different Si/Al ratios were studied for the selective reduction of NO by propylene under lean burn conditions. It was observed that the conversion of NO was increased with the increase of Si/Al ratio when the exchange degree of copper was below 100%. Temperature programmed reduction and desorption were also employed to investigate the reducing capacities and adsorption/desorption characteristics of the catalyst. The results showed that the Si/Al ratio had an effect on the electrostatic interaction between copper ions and Al MCM 41 framework. Thus the change of concentration and characteristics of the active center (Cu 2+ ) affected the catalytic activity for NO reduction.