Ce改性Pd基整体式催化剂的结构特征及其甲烷催化燃烧性能

分别以拟薄水铝石和添加Ce的拟薄水铝石制备铝溶胶，经过堇青石（Cord）表面涂覆和Pd溶液浸渍，得到浸渍法和溶胶法Ce改性的Pd/γ-Al₂O₃/Cord整体式催化剂。采用XRD、SEM和XPS等对催化剂进行表征，评价其甲烷催化燃烧反应性能，并考察Ce的不同添加方式对催化剂结构和反应性能的影响。结果表明，适量Ce的添加可提高Pd基整体式催化剂的甲烷催化燃烧性能，溶胶法优于浸渍法。随着Ce添加量的增加，浸渍法改性的Pd基催化剂催化性能有所降低，溶胶法则呈现先升高后降低的趋势。溶胶法中Ce的添加物与γ-Al₂O₃涂层充分融合，提高了涂层的热稳定性和活性组分的分散度，0.5Pd/γ-Al₂O₃(3.0Ce)/Cord催化剂催化性能最优。

Catalytic combustion of lean methane over Pd/γ-Al2O3/Cord monolith catalysts modified by Ce

The Pd/γ-Al₂O₃/Cord monolithic catalysts modified by cerium were prepared by impregnation method and sol-gel method.The catalysts were characterized by XRD,SEM and XPS techniques.The effect of the different ways of adding cerium on the catalytic performance and structure of the catalysts for the methane catalytic combustion was investigated.The results indicated that the appropriate amount of cerium significantly improved the catalytic performance of the Pd-based monolithic catalysts for lean methane catalytic combustion and the catalysts prepared by sol-gel method slightly exceeded the ones obtained by impregnation method.With the increase of cerium,the catalytic performance of the catalysts prepared by impregnation method decreased,and that of the catalysts prepared by sol-gel method increased at first and then decreased.Since the cerium additive of the catalyst prepared by sol-gel method combined well with γ-Al₂O₃,the thermal stability of the coating and the dispersion of the active components were improved,and 0.5Pd/γ-Al₂O₃(3.0Ce)/Cord catalyst exhibited the best catalytic properties.