制备方法对Pd催化剂上丙烯选择性还原NO反应性能的影响  

Effects of Preparation Methods on Pd Catalysts for Selective Catalytic Reduction of NO by Propene

作　　者：刘振林[1] 伏义路[1] 

机构地区：[1]中国科学技术大学化学物理系,合肥230026

出　　处：《催化学报》2001年第1期62-66,共5页

基　　金：中国-福特研究和发展基金! (9712 30 1)资助项目

摘　　要：采用三种不同方法制备了氧化铝负载的Pd催化剂 .比表面积测定结果表明 ,与浸渍法相比 ,溶胶 凝胶加浸渍法和溶胶 凝胶法制备的Pd/Al2 O3 样品具有较大的比表面积 ,但抗烧结性能不佳 .其中采用溶胶 凝胶法制备的样品中 ,由于Pd分散于体相中 ,表面的活性位相对较少 ,造成催化剂在NO选择性还原反应中的活性较差 ;而将Pd浸渍于溶胶 凝胶法制得的Al2 O3 载体上所获得的催化剂比表面积较大 ,活性较好 .添加CeO2 的样品活性总体上比Pd/Al2 O3 样品高 .其中采用溶胶 凝胶法制备的样品比表面积不大 ,并且XRD数据表明Al2 O3 和CeO2 是高度分散并均匀地搀杂在一起的 ,不象在浸渍法制备的样品中那样以大晶粒的形式存在 ,因而CeO2 的助剂作用没有充分体现出来 ,催化剂的活性比浸渍法制备的样品差一些 .Alumina-supported Pd catalysts were prepared by three different methods: impregnation (im), sol-gel-impregnation (gel-im) and sol-gel (gel) . The surface area measurement implies that, for the sample Pd/Al2O3, using gel-im and get methods can achieve high surface area compared with using im method, but the samples sinter heavily at high temperature. Pd/Al2O3 sample prepared by one-step get method shows lower activity in the selective catalytic reduction of NO, because Pd may exist in bulk phase; while the samples prepared by impregnating Pd onto the sol-gel-made Al2O3 support have high surface area and high activity. The addition of CeO2 increases the activity of all samples. The gel-im and gel methods have no advantage over im method on aspect of surface area; furthermore, the XRD data show that CeO2 is well mixed with Al2O3 in the form of high dispersion, instead of existing as big crystalline as in the case of im method. This hinders the promoter effect of CeO2 and decreases the catalyst activity.

关 键 词：钯 氧化铝 负载型催化剂 浸渍法 溶胶-凝胶法 一氧化氮 制备 丙烯 

分 类 号：O643[理学—物理化学]