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用脉冲反应技术和中毒滴定方法考察了不同条件制备的Pt-Sn 双金属催化剂上乙烯加氢反应的动力学参数和活性中心浓度,试图阐明催化剂的制备条件与其反应动力学行为的关系。结果表明,尽管催化剂的铂、锡含量相同,由于制备条件不同,乙烯加氢表观反应速率常数是不同的。这是因为催化剂的吸附性能和表面反应速率发生了改变的缘故,而后两者又是来源于不同制备条件下催化剂上所形成的活性中心浓度、类型与比例之间的差异。这种不同类型的活性中心及不同的反应性能又被认为是在不同制备条件下金属与载体间相互作用不同所造成的。
The kinetics parameters and concentration of active sites of ethylene hydrogenation on Pt-Sn bimetallic catalysts prepared under different conditions were investigated by pulse reaction and poisoning titration in order to elucidate the relationship between the preparation conditions and the reaction kinetics. The results show that although the catalyst has the same platinum and tin contents, the apparent hydrogenation reaction rate constants are different due to different preparation conditions. This is due to the change in the adsorption performance and the surface reaction rate of the catalyst, which in turn is derived from the difference in concentration, type and ratio of active sites formed on the catalyst under different preparation conditions. The different types of active centers and different reactivity are again thought to be caused by the different interactions between the metal and the support under different preparation conditions.