利用CO和NO吸附的红外光谱表征还原态的Ru-Co-Mo/Al_2O_3催化剂

AN INFRARED CHARACTERIZATION OF REDUCED Ru-Co-Mo/A\_2O_3 CATALYST BY CO AND NO ADSORPTION

用CO和NO吸附的红外光谱表征了还原态的Ru-Co-Mo/Al_2O_3催化剂。结果表明,和Ru/Al_2O_3相比,CO吸附于Ru-Co-Mo/Al_2O_3的Ru中心上的红外谱带向高波数移动;和Co-Mo/Al_2O_3相比,CO和NO吸附在Ru-Co-Mo/Al_2O_3的Co、Mo中心上的特征谱带向低波数移动;通过TPD-IR还可看到,CO和NO在Ru-Co-Mo/Al_2O_3的吸附量及脱附温度大大地提高了。这些结果说明在Ru-Co-Mo/Al_2O_3的Ru中心上的部分电子转移到Co、Mo中心或其周围,或者Ru中心的存在促进了Co、Mo中心的还原。

An investigation has been performed on the adsorption of CO and CO + NO on reduced Ru/Al_2O_3,Co-Mo/Al_2O_3 and Ru-Co-Mo/Al_2O_3 catalysts. In contrast to Ru/Al_2O_3 and Co-Mo/Al_2O_3, the infrared absorption band frequencies of CO adsorbed on Ru sites of the Ru-CoMo/Al_2O_3 were shifted to higher wavenumbers. On the other hand, the infrared bands associated with the adsorption of CO and NO on Co and Mo sites in Ru-Co-Mo/Al_2O_3 were shifted to lower frequencies. In TPD-IR studies, the adsorption of CO and NO on Co and Mo sites in the Ru-Co-Mo/Al_2O_3 catalyst was stronger than that in Co-Mo/Al_2O_3.From the above results, it was proposed that the d electrons of Ru sites were partly transferred to Co and Mo sites or/and the presence of Ru sites promoted the reduction of Co and Mo sites in the Ru-Co-Mo/Al_2O_3.