Pd - Cu/凹凸棒石黏土催化剂催化CO氧化性能

摘要

Using attapulgite clay (APT) as the support, the bimetallic Pd-Cu/APT catalyst, monometallic Pd/APT and Cu/APT catalysts were prepared by wet impregnation method. The catalytic activities of the catalysts for CO oxidation were investigated in a fixed-bed continuous flow reactor and characterized by N2 physisorption,XRD,H2-TPR and NH3-TPD. The result of XRD showed that Cu species in Pd-Cu/APT catalyst existed mainly in the form of CuCl phase. There existed obvious interaction between Cu species and highly dispersed Pd species in Pd-Cu/APT catalyst. The TPR results indicated that the reduction temperature of Cu species were reduced due to the stronger interaction between Pd and Cu. NH3-TPD characterization showed that surface acidity of the catalyst was enhanced after the pretreatment of water vapor. As a result,the catalyst exhibited excellent performance for CO oxidation. CO conversion of 90% on Pd-Cu/ APT catalyst was attained under the reaction condition of 0.5vol%CO,GHSV 6 000 h-1,3.3vol% water vapor and room temperature.%以凹凸棒石黏土(APT)作载体,采用浸渍法制备双金属催化剂Pd - Cu/APT、单金属催化剂Pd/APT和Cu/APT,在连续流动微反装置上考察催化剂的CO催化氧化活性,采用N2物理吸附/脱附、X射线粉末衍射和程序升温还原/脱附等手段对催化剂进行表征.结果表明,Pd - Cu/APT催化剂中Cu主要以CuC1形式存在,Pd高度分散与Cu之间产生了明显的相互作用,使Cu物种的还原温度大幅降低；经水蒸汽预处理增强了Pd - Cu/APT催化剂表面酸性,促进了催化活性的提高.在CO体积分数为0.5％、水蒸汽体积分数3.3％、空速6000h-1和常温反应条件下,CO转化率可达90％以上.