Pd/CeO 2 catalysts with different metallic Pd loading were synthesized by impregnation method. The physicochemical properties of prepared Pd/CeO 2 catalysts and corresponding precursors were studied by XRD, XPS, H 2 -TPD and H 2 -TPR. Moreover, the catalytic performance of the Pd/CeO 2 catalysts was investigated via gas phase benzene hydrogenation reaction at the temperature of 100–200 °C under atmosphere pressure. Results show that the catalytic performance of prepared Pd/CeO 2 catalysts is directly related to the metallic Pd content. The amounts of active metallic Pd and adsorbed-desorbed hydrogen species on Pd/CeO 2 catalysts increase with the increasing metallic Pd loading from 1.0 to 3.0%, while the numbers of them are slightly reduced on Pd/CeO 2 (3.5) catalyst. Furthermore, metallic Pd is highly dispersed on the nano-CeO 2 supports, therefore, the prepared Pd/CeO 2 catalysts present good gas phase benzene catalytic hydrogenation performance. At 200 °C, the benzene conversion over the Pd/CeO 2 catalysts with different metallic Pd loading follows the rule: Pd/CeO 2 (3.0) > Pd/CeO 2 (3.5) > Pd/CeO 2 (2.5) > Pd/CeO 2 (2.0) > Pd/CeO 2 (1.5) > Pd/CeO 2 (1.0), corresponding values are 94.3, 96.4, 89.9, 82.8, 72.7, 42.6 and 94.3%. And the cyclohexane selectivity is 100% on all prepared Pd/CeO 2 catalysts.

中文翻译：

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Pd/CeO2催化剂的催化加氢性能研究

采用浸渍法合成了不同金属Pd负载量的Pd/CeO 2 催化剂。采用XRD、XPS、H 2 -TPD和H 2 -TPR对制备的Pd/CeO 2 催化剂及相应前驱体的理化性质进行了研究。此外，Pd/CeO 2 催化剂的催化性能通过气相苯加氢反应在100-200 ℃的温度和大气压下进行了研究。结果表明，制备的Pd/CeO 2 催化剂的催化性能与金属Pd含量直接相关。Pd/CeO 2 催化剂上活性金属Pd和吸附-解吸氢物种的数量随着金属Pd负载量从1.0%增加到3.0%而增加，而在Pd/CeO 2 (3.5)催化剂上它们的数量略有减少。此外，金属 Pd 高度分散在纳米 CeO 2 载体上，因此，制备的Pd/CeO 2 催化剂表现出良好的气相苯催化加氢性能。200 ℃时，不同金属Pd负载量的Pd/CeO 2 催化剂的苯转化率遵循以下规律：Pd/CeO 2 (3.0) > Pd/CeO 2 (3.5) > Pd/CeO 2 (2.5) > Pd/ CeO 2 (2.0) > Pd/CeO 2 (1.5) > Pd/CeO 2 (1.0)，对应值为94.3、96.4、89.9、82.8、72.7、42.6和94.3%。并且在所有制备的Pd/CeO 2 催化剂上环己烷选择性为100%。89.9、82.8、72.7、42.6 和 94.3%。并且在所有制备的Pd/CeO 2 催化剂上环己烷选择性为100%。89.9、82.8、72.7、42.6 和 94.3%。并且在所有制备的Pd/CeO 2 催化剂上环己烷选择性为100%。