Mn-Ce/(CC-A)@12TiO_2整体式蜂窝催化剂的制备及脱硝性能研究

Preparation and performance for NO_x removal of Mn-Ce/(CC-A)@12TiO_2 monolith honeycomb catalyst

以氨水预处理后的堇青石蜂窝陶瓷为基体,采用半原位溶胶-凝胶工艺制备涂覆TiO_2涂层的Mn-Ce/(CC-A)@12TiO2整装脱硝催化剂,在80～260℃,NOx转化率达90%以上。N2吸脱附、XRD、TG-DSC等分析测试表明,TiO_2主要以结构完整的锐钛矿晶型存在,促进了活泼氧物质的生成,提高了催化活性。SEM图像表明,催化剂表面TiO_2涂层上具有裂纹和粗糙表面,有利于三维结构以及更多孔结构的形成,为反应物与活性位之间相互作用产生更多的活性中间体,从而促进反应速率提供了适宜的场所。EDS研究显示,催化剂Mn-Ce/(CC-A)@12TiO2中TiO_2表面形成的弱结晶Mn-Ce混合氧化物可能有利于Mn与Ce的微观协同效应,提高中间体的形成。

Pretreating of CC with NH3·H2O and coating of TiO2 with semi-in-situ sol-gel method over CC-A were propitious to low-temperture catalytic performance of NH 3-SCR over monolith catalyst Mn-Ce/(CC-A)@12TiO2,with above 90%conversion of NO x during 80~260℃.Results of N 2-adsorption/desorption,XRD and DSC indicated that TiO2 mainly existed in intact anatase crystalline which accelerated the generation of labile oxygen species with contribution to activity.SEM images demonstrated that three-dimensional structure and more channels were formed over catalyst surface due to fissures and rough surface of special TiO 2 coating,which was conducive to interaction between reactants and active sites generating more reactive intermediates to accelerate reaction rate.EDS result showed that,Mn-Ce mixed oxides with weak crystalline over Mn-Ce/(CC-A)@12TiO2 might facilitate the synergistic effect between Mn and Ce to enhance the formation of intermediates as well.