在CeO_2-ZrO2中加入La_2O_3对改善单Pd三效催化剂性能的作用  

Effect of La_2O_3 in CeO_2-ZrO_2 on Catalytic Performance of Pd-only Three-way Catal yst

作　　者：蒋平平[1] 卢冠忠[1] 郭杨龙[1] 郭耘[1] 王筠松[1] 张顺海[1] 王幸宜[1] 

机构地区：[1]结构可控先进功能材料及其制备教育部重点实验室华东理工大学工业催化研究所

出　　处：《无机化学学报》2004年第12期1390-1396,共7页Chinese Journal of Inorganic Chemistry

基　　金：上海市纳米科技专项基金(No.0123nm025);上海市科技发展基金(No.033012001)

摘　　要：浸渍法制备了CeO2鄄ZrO2鄄La2O3复合氧化物,用XRD、热分析(TG鄄DTA,DSC)、BET表面积、H2鄄TPR等对合成样品进行表征,研究了La2O3的加入对CeO2鄄ZrO2和单钯Pd/CeO2鄄ZrO2/γ鄄Al2O3/蜂窝陶瓷催化剂性能和热稳定性的影响。结果表明,在CeO2鄄ZrO2鄄La2O3中,La的存在能促进CeO2鄄ZrO2固溶体的还原,提高贮氧能力;在Pd/CeO2鄄ZrO2/γ鄄Al2O3中加入La有利于提高催化剂的耐热稳定性,阻止γ鄄Al2O3在高温下的晶相转变,进一步稳定Al2O3的结构,保持其高的表面积。在贵金属Pd的负载量为1g·L-1的条件下,测定了Pd/CeO2鄄ZrO2鄄La2O3/γ鄄Al2O3/蜂窝陶瓷催化剂对CO、C3H8和NOx的三效催化净化活性。结果表明,在Pd/CeO2鄄ZrO2/Al2O3/蜂窝陶瓷催化剂中加入La2O3后,能明显地改善催化剂的低温活性和三效催化性能,经1000℃老化10h后,CO、C3H8和NOx净化的起燃温度(T50)分别为330℃、350℃和380℃。The CeO2-ZrO2-La2O3 mixed oxides were prepared by co-precipitation method and characterized by XRD, TG-DTA, TG-DSC, BET surface area and H-2-TPR. The effects of La2O3 addition on CeO2-ZrO2 and Pd-only/gammaAl(2)O(3)/ceramic honeycomb's catalytic performance and thermal stability were studied. The results show that the La2O3 addition in CeO2-ZrO2 is beneficial to promote the reduction of CeO2-ZrO2 solid solution, to improve its oxygen storage capacity, to suppress transformation of gamma-Al2O3 into others, and further to increase the structure stability of alumina, thus keeping the high surface area of catalyst. The three-way catalytic activity of Pd/CeO2-ZrO2La2O3/gamma-Al2O3/ ceramic honeycomb was measured for a simulated exhaust gas containing CO, C(3)A(8,) O-2 and NO, when the loading of Pd was 1 g.L-1 on catalyst. It is found that the presence of La2O3 can improve remarkably the low temperature catalytic activity and three-way catalytic performance of the catalyst. Over the Pd/CeO2-ZrO2La2O3 /gamma-Al2O3 / ceramic honeycomb catalyst aged at 1000 degreesC for 10 h, the initial light-off temperature (T-50) for CO, C(3)A(8) and NOx was 350 degreesC, 355 degreesC and 380 degreesC, respectively.

关 键 词：钯 三效催化剂 铈锆镧复合氧化物 浸渍法 制备 催化性能 表面积 汽车排气污染 净化 

分 类 号：X734.2[环境科学与工程—环境工程] TQ426.96[化学工程]