蜂窝状Ti_(0.14)Mn_(0.86)O_x/CH催化剂的制备及其低温NH_3-SCR脱硝性能  

Preparation and investigation of Ti_(0.14)Mn_(0.86)O_x/CH monolithic catalysts for low-temperature NH_3-SCR

作　　者：张先龙[1] 刘鹏[1] 蔡程[1] 吴雪平[1] 郭亚晴 

机构地区：[1]合肥工业大学化学与化工学院,合肥230009

出　　处：《环境化学》2016年第10期2146-2155,共10页Environmental Chemistry

基　　金：国家自然科学基金(40902020;51002042);高等学校博士学科点专项科研新教师基金(120090111120019);中央高校基本科研业务费专项基金(2011HGQL1003)资助~~

摘　　要：采用自蔓延高温合成法(SHS)以堇青石蜂窝陶瓷(CH)为基体制备了一系列Ti_(1-y)MnyO_x/CH整体式催化剂,应用于柴油车尾气氮氧化物净化.考察了制备参数(钛锰比、涂覆次数、点燃温度)和工况条件(空速,水蒸气)对催化剂低温SCR(选择性催化还原)脱硝活性的影响,采用X射线荧光光谱仪(XRF)、场发射扫描电镜(FE-SEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)、比表面积(BET)等表征手段对催化剂的结构和形貌进行表征.结果表明,在Ti∶Mn=1∶6(物质的量之比),一次涂覆,点燃温度为350℃条件下所制备的催化剂具有最佳的NH_3-SCR脱硝活性,Ti_(0.14)Mn_(0.86)O_x/CH催化剂在空速为30000 h^(-1),氧气含量为3 vol%反应温度为150—250℃时反应条件为最优,催化剂在150℃以上具有良好的耐水性.Ti元素的添加提高了催化剂表面Mn^(4+)/Mn^(3+)比例,并使MnO_x呈无定形态均匀分散在Ti_(0.14)Mn_(0.86)O_x/CH催化剂表面,提高催化剂的低温SCR活性.Cordierite honeycomb ceramics（ CH） as catalysts＇ carrier were prepared by selfpropagating high-temperature syntheses method（ SHS） to obtain a series of Ti1-yMnyOx/ CH catalysts for diesel exhaust purification. The effects of the preparation parameters（ Ti / Mn ratio in the combustion solution, times of coating, ignition temperature） and operation conditions（ space velocity and H2O） on performance of the monolith catalysts for the NH3-SCR were also investigated.The catalysts were characterized by BET,XRF,XRD,FESEM and XPS. It was observed that the catalysts ignited at 350 ℃ once with Ti / Mn = 1 ∶ 6 in the combustion solution showed the optimal NH3-SCR activity when tested at 150—250 ℃ with NH3/ NO ratio at 1,gaseous hourly space velocity（ GHSV） = 30000 h^-1and 3vol% O2. The catalyst showed excellent H2O tolerance when temperature was above 150 ℃. Addlition of Ti in the combustion solution increased Mn^4＋/ Mn^3＋ratio and improved uniform distribution of amorphous Mn Oxon the surface of the catalysts,which arebenefit for the NH3-SCR activity of the catalysts.

关 键 词：自蔓延高温合成 锰基催化剂 脱硝 低温SCR 

分 类 号：X734.2[环境科学与工程—环境工程] O643.36[理学—物理化学]