负载型CeO2-ZrO2固溶体的性能及其在甲烷燃烧Pd催化剂中的应用

摘要

CeO2-ZrO2 solid solution was supported on Si-modified alumina(Ce-Zr-O/Si-Al2O3)by the reverse microemulsion method.Its structure,thermal stability,and oxygen release capacity were studied by N2 adsorption,XRD,TPR,Raman spectroscopy,and XPS.The crystalline phase of Ce-Zr-O on Si-Al2O3 was the same as that of unsupported CeO2-ZrO2(Ce-Zr-O),but its thermal stability,oxygen release capacity at low temperature,and total oxygen storage capacity were higher.As the support of a Pd catalyst for methane combustion,Ce-Zr-O/Si-Al2O3 had better properties than Ce-Zr-O,Si-Al2O3,and the mixture of Ce-Zr-O+Si-Al2O3.Using the 0.2% Pd/10%Ce-Zr-O/Si-Al2O3 catalyst,T90 for methane combustion was only 345℃,which was 175℃ lower than that of Pd supported on other supports.%以硅改性的氧化铝为载体,用反相微乳液法合成了负载型的CeO2-ZrO2固溶体(Ce-Zr-O/Si-Al2O3),用低温氮吸附、X射线衍射、程序升温还原、拉曼光谱和x射线光电子能谱等方法对Ce-Zr-O/Si-Al2O3的织构性能、热稳定性和储放氧性能等进行了表征.结果表明,负载后的CeO2-ZrO2晶相与负载前相比没有变化,但热稳定性和在低温下的放氧能力及总储氧量明显提高.作为甲烷燃烧Pd催化剂的载体,Ce-Zr-O/Si-Al2O3的性能明显优于CeO2-ZrO2,Si-Al2O3和机械混合物CeO2-ZrO2+Si-Al2O3.使用0.2%Pd/10%Ce-Zr-O/Si-Al2O3为催化剂时,甲烷90%转化率时的温度仅为345℃,比负载在其它载体上的Pd催化剂低175℃.