类水滑石衍生CuAlO催化剂同时去除碳颗粒和氮氧化物  

Simultaneous Catalytic Removal of NO_x and Diesel Soot over Cu-Containing Hydrotalcite Derived Catalysts

作　　者：王仲鹏[1,2] 陈铭夏[1] 上官文峰[1] 

机构地区：[1]上海交通大学机械与动力工程学院,燃烧与环境技术研究中心,上海200240 [2]济南大学化学化工学院,济南250022

出　　处：《物理化学学报》2009年第1期79-85,共7页Acta Physico-Chimica Sinica

基　　金：GM(通用汽车)-中国科学研究基金(50222203);上海市科委纳米专项基金(0652nm048)资助项目

摘　　要：以共沉淀法合成的含Cu类水滑石为前驱物,制备了具有介孔结构的CuAlO复合氧化物催化剂,采用程序升温反应技术评价了催化剂同时去除碳颗粒物(soot)和氮氧化物的性能,并系统分析了反应条件对催化活性的影响.结果表明,在紧接触和松接触两种条件下,CuAlO都有较高的同时去除碳颗粒物和NOx的催化活性,当催化剂与soot由紧接触变为松接触时,起燃温度(Ti)由260℃升高到314℃,NO转化为N2的最大转化率(XN2-max)值由40.4%下降为29.2%;soot含量不同对Ti影响不大,Ti都在260℃左右;NO浓度或O2浓度增加,Ti下降,O2浓度从2.5%增至7.5%时对XN2-max影响不大,都在40%左右;反应气流速增大,soot起燃温度Ti基本不变,都在260℃左右,而XN2-max随气速增加而减小,当气速从20mL·min-1升至80mL·min-1时,XN2-max由40.4%下降至21.6%,但生成N2的量基本相同,这取决于催化剂的选择性.催化剂经重复使用后活性下降,可能是由于反应过程中生成的中间产物吸附于催化剂表面,覆盖了催化剂表面的活性位.Copper-containing mixed oxides （CuAlO） were derived from hydrotalcites and prepared by co-precipitation and thermal evolution methods. The catalytic activity of the CuAIO was investigated for the simultaneous catalytic removal of NOx and diesel soot particulates by a temperature-programmed reaction （TPR） technique in a fixed-bed flow reactor. CuAlO showed good activity for the NOx-soot removal reaction under both tight and loose contact conditions. When the contact conditions between catalyst and soot changed from tight to loose, the ignition temperature （Ti） increased from 260 ℃ to 314 ℃ while the maximum conversion of NO to N2 （XN2-max） decreased from 40.4% to 29.2%. Soot content had no effect on the ignition temperature and all the Ti values were about 260 ℃ for different soot content. With an increase in NO concentration or O2 concentration the Ti value decreased. XN2-max values were about 40% when the O2 concentration changed from 2.5% to 7.5%. The total flow rate had no effect on the Ti values, while the XN2-max decreased from 40.4% to 21.6% when the total flow rate increased from 20 to 80 mL ·min^-1. Catalytic activity decreased when the catalyst was reused and this decrease may be related to an intermediate absorbed on the catalyst surface.

关 键 词：水滑石 复合氧化物 碳颗粒物 氮氧化物 催化去除 

分 类 号：O643.32[理学—物理化学]