低温等离子体协同Ag/Al_2O_3选择性催化丙烯还原氮氧化物反应的原位红外光谱研究  

In Situ DRIFTS Study on Non-thermal Plasma-Assisted NO_x Reduction by Propene over Ag/Al_2O_3 Catalyst

作　　者：柯锐[1] 李俊华[2] 郝吉明[2] 傅立新[2] 陈强[1] 赵大庆[1] 

机构地区：[1]清华大学机械工程系,北京100084 [2]清华大学环境科学与工程系,北京100084

出　　处：《催化学报》2005年第11期951-955,共5页

基　　金：国家高技术研究发展计划(863计划)项目(2004AA649150);国家自然科学基金重点项目(20437010)资助

摘　　要：研究了稀燃条件下低温等离子体(NTP)协同丙烯在Ag/Al2O3催化剂上选择性催化还原NOx反应,通过原位漫反射傅里叶变换红外光谱(DRIFTS)对NTP协同前后反应气中NO和C3H6的吸附以及丙烯选择性催化还原反应进行了表征.结果表明,丙烯的活化是Ag/Al2O3上选择性催化还原反应的关键步骤.NTP活化反应气体后,Ag/Al2O3表面-NCO、R-NO2和有机酸根等物种的数量大幅度增加,并且其催化还原NOx的低温(<350℃)活性也显著提高.在NTP协同前后,选择性催化还原过程可能存在两条反应路径,较低温度下主要是-NCO生成N2,而较高温度下则是-CN向N2转化.The non-thermal plasma （NTP）-assisted selective catalytic reduction （SCR） of NO, by propene over the Ag/Al2O3 catalyst was investigated. In situ diffuse reflectance infrared Fourier transform spectroscopy （DRIFTS） studies were carried out on the NO and C3H6 adsorption and SCR reactions over Ag/Al2O3 with or without NTP pretreatment. The results showed that the low-temperature activity of C3H6-SCR was remarkably enhanced with the assistance of NTP in the presence of excess oxygen. The activation of propene was the key step in C3H6-SCR over Ag/Al2O3. After the application of NTP, the amount of -NCO, R-NO2 and organic acid species over Ag/Al2O3 significantly increased, which caused a high catalytic activity at low temperatures （〈350℃ ）. Two reaction paths were proposed in both SCR and NTP-SCR. At low reaction temperatures, -NCO was the key intermediate to generate N2, while it was -CN at high reaction temperatures.

关 键 词：低温等离子体 银 氧化铝 选择性催化还原 稀燃 氮氧化物 原位漫反射傅里叶变换红外光谱 

分 类 号：O643.3[理学—物理化学]