纳米CeO_2载体对Au-Pd催化剂性能的影响  

Influence of Nano-ceria Support on Catalytic Performance of Au-Pd Catalysts

作　　者：李苑[1,2] 罗来涛[1] 李长全[3] 

机构地区：[1]南昌大学应用化学研究所,江西南昌330031 [2]江西师范大学化学化工学院,江西南昌330022 [3]南昌大学材料科学与工程学院,江西南昌330031

出　　处：《精细化工》2009年第10期974-977,995,共5页Fine Chemicals

基　　金：高等学校博士学科点专项科研基金(20040403011);江西省教育厅科技项目(GJJ08021)~~

摘　　要：采用十六胺和不同铈前驱体(硝酸铈铵或硝酸亚铈)分别合成了纳米CeO2(H4和H3),考察了纳米CeO2载体的织构性质对Au-Pd催化剂甲醇部分氧化制氢(POM)性能的影响,用HRTEM、N2吸附、XRD和TPR等对样品进行了表征。结果表明,铈前驱体对载体的性能有较大的影响,以硝酸铈铵为前驱体所制H4载体具有较小的粒径(约5 nm)和平均孔径(5.3 nm)、较大的比表面积(243 m2/g),而硝酸亚铈所制H3载体具有较大的平均孔径(7.9 nm)。POM结果表明,纳米CeO2负载的Au-Pd催化剂具有较好的催化性能,300℃时,Au-Pd/H3的活性和H2选择性分别达100%和59.7%。低温时催化剂的活性和H2选择性为:Au-Pd/H3>Au-Pd/H4,而高温时顺序相反,这是由于低温时催化剂的孔径对反应物和产物的扩散影响较大,高温时催化剂的比表面积和活性组分分散度起主要作用。With the surfactant hexadecylamine and different cerium precursors（ammonium ceric nitrate or cerous nitrate）,nano-ceria were prepared and denoted with H4 and H3,respectively.The effect of the texture properties of nano-ceria on the performance of supported Au-Pd catalysts for the partial oxidation of methanol（POM） has been evaluated.The supports and the catalysts were characterized by HRTEM,N2 adsorption,XRD and TPR.The results indicate that cerium precursor has a great influence on the texture properties of support. H4 prepared from ammonium ceric nitrate exhibits the smaller grain size （ca. 5 nm）, average pore size （5.3 nm） and larger surface area （243 m2/g） while H3 synthesized from cerous nitrate shows a larger average pore size （7.9 nm）. The results of POM reveal that nano-ceria supported Au-Pd catalysts have good catalytic performance,in which the activity and H2 selectivity of Au-Pd/H3 are 100% and 59.7% , respectively. Au-Pd/H3 exhibits a higher catalytic activity and H2 selectivity than Au-Pd/H4 at lower reaction temperature while the reverse happens at higher reaction temperature. It is because that pore size of catalysts has greater effect on the diffusion of reactants and products at lower reaction temperature while surface area and the dispersion of active components of catalysts play the major role in its catalytic performance at higher reaction temperature.

关 键 词：制氢 甲醇部分氧化 Au-Pd催化剂 纳米CEO2 

分 类 号：O643[理学—物理化学]