CeO2-WO3复合氧化物催化剂的NH_3-SCR反应机理(英文)  

Mechanism of Selective Catalytic Reduction of NO_x with NH_3 over CeO_2-WO_3 Catalysts

作　　者：陈亮[1,2] 李俊华[2,3] 葛茂发[1] 马磊[2] 常化振[2] 

机构地区：[1]中国科学院化学研究所分子动态与稳态结构国家重点实验室,北京100190 [2]清华大学环境科学与工程系,北京100084 [3]清华大学环境模拟与污染控制国家重点实验室,北京100084

出　　处：《催化学报》2011年第5期836-841,共6页

基　　金：国家自然科学基金(51078203);国家高技术研究发展计划(863计划,2007AA0618023 and 2006AA06A304)~~

摘　　要：采用共沉淀法制备了新型CeO2-WO3复合氧化物催化剂,并用于氨选择性催化还原（NH3-SCR）NOx反应中.活性测试表明,在200-450oC NOx转化率接近100%.采用程序升温脱附和原位漫反射红外光谱研究了该催化剂上的NH3-SCR反应机理.结果表明,该催化剂的主要活性位是CeO2,而WO3的加入大大提高了其表面Brnsted酸位的数量与强度及其氧化NO的能力.另外还发现,除了催化剂表面Lewis酸与Brnsted酸参与反应外,表面的桥式与单齿硝酸盐也是活性很高的物种.整个SCR反应可通过以上两种途径进行.The mechanism of NH3-selective catalytic reduction（SCR）over a CeO2-WO3 catalyst was investigated by temperature-programmed desorption（TPD）analysis and in situ diffuse reflectance infrared Fourier transform spectroscopy.The active sites were on CeO2,while WO3 greatly enhanced the amount and strength of the surface Br？nsted acid sites and the NO oxidation ability.Both NH4 ＋ and coordinated NH3 contributed to the SCR reaction.Bridging nitrate and monodentate nitrate were confirmed as the reactive nitrate species. Under SCR reaction conditions,surface NH4NO3 was formed,which played the role of an important intermediate species.Two different pathways for the SCR reaction were suggested for the CeO2-WO3 catalyst.

关 键 词：氮氧化物去除 选择性催化还原 活性 一氧化氮氧化能力 机理 

分 类 号：O643.32[理学—物理化学]