Pd-M/Al_2O_3催化CH_4燃烧反应性能及其活化能表征

Characterization of Reactivity and Activation Energy for Catalytic Combustion of Methane on Pd-M/Al_2O_3

以γ-Al2O3为载体,浸渍法分别负载助剂CeO2,MgO,K2O,ZrO2和活性组分PdO制备催化剂PdO-M/Al2O3.在微型固定床反应器中测试催化剂的反应活性.应用TPD和TPR表征催化剂表面吸附性能.依据TPR曲线计算其H2-TPR活化能,评价催化剂的活性与反应活化能之间的关系.结果表明,催化剂2%PdO/Al2O3的催化活性较好,在380℃CH4即完全氧化;在温度一定的条件下,反应速率是由反应活化能和反应指前因子共同决定的;不同催化剂对同一反应过程中指前因子和活化能的影响也不同.

Withγ-Al2O3as the carrier,promoters CeO2,MgO,K2O,ZrO2and active component PdO were loaded on the support by an impregnation method.The activity of catalysts was tested in a fixed-bed micro reactor.The surface adsorptive property of catalysts was characterized by a TPD and TPR.The H2-TPR activation energy of catalyst was calculated according to TPR curve,which can evaluate the relationship between the activation energy and the catalytic activity of catalyst.The results show that the 2%PdO/Al2O3exhibits a higher activity with CH4totally oxidized at 380℃.At the same reaction temperature,the reaction rate is dependent on not only the activation energy,but also the pre-exponential factor.For the same reaction,different catalysts have different influences on the activation energy and the pre-exponential factor.