低温等离子体协同Ag/γ-Al_2O_3选择性催化还原NO_x  

Non-thermal plasma-assisted selective catalytic reduction of NO_x over Ag/γ-Al_2O_3

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

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：《清华大学学报（自然科学版）》2006年第8期1349-1352,共4页Journal of Tsinghua University(Science and Technology)

基　　金：国家"八六三"高技术项目(2004AA649150)

摘　　要：为有效去除汽油车和柴油车尾气中的NOx，研究了低温等离子体（non—thermal plasma，NTP）活化不同气体组分对Ag／γ—Al2O3催化剂上C3H6选择性催化还原（selective catalytic reduction，SCR）NOx的作用，通过原位漫反射红外光谱对比了NTP协同前后SCR反应中间物种的变化，并考察了O2浓度和SO2对NTP协同C3H6-SCR反应的影响。结果表明，NTP协同在200～400℃显著提高SCR反应活性，NTP中C3H6的氮化和氧化反应对协同作用有最大贡献，使得SCR反应中含氧有机物、NCO、CN等关键中间物种明显增加，而NTP单独活化NO＋O2或O2对SCR促进作用不大。在2．5％～25％氧浓度、含0．01％S0。条件下NTP协同对SCR的低温（〈350℃）活性均有明显提高。To find effective method removing NOx from the exhaust of diesel and petrolie motor, the activity of selective catalytic reduction （SCR） of NOx in non-thermal plasma （NTP）-assisted catalysis was investigated. The influence of SO2, and O2 concentration was also examined. The results show that activity of selective catalytic reduction of NOx with propene （C3Ha-SCR） was significantly enhanced at 200 - 400℃ by NTP assistance over Ag/γ-Al2O3. For high Oz concentration and 0.01% SOz, the activity of NTP-assisted SCR was still better than thermal SCR below 350℃. The propene activation more effectively enhanced the activity than NO oxidation to NO2 or O2 activation to O3. In situ diffuse reflectance infra-red Fourier transform spectroscopy （DRIFTS） studies of the intermediates of NTP-assisted and thermal C3H6-SCR found that, at 250C, the surface nitrates decreased with increase of key intermediates for SCR such as NCO, CN, R-NQ and organic acids. The increases in these intermediates arc provably related to the low temperature promotion of activities in NTP-assisted SCR.

关 键 词：选择性催化还原 低温等离子体 NOx 协同催化 原位漫反射红外光谱 

分 类 号：O643.3[理学—物理化学]