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寻找适当的载体,了解载体对于活性组分的分散以及分散态结构的影响,长期以来,一直是催化工业研究中的一项重要工作和催化理论研究中最引人注目的课题之一。由于未能找到一种强有力的手段,直接观察不同载体催化剂中活性组分分散后的结构变化,长期来人们虽然已经做了大量的工作,但是至今催化剂的筛选仍未能完全摆脱“炒菜”的模式,对某些催化体系虽也提出了一些载体的和催化剂的作用机理模型,终因缺乏直接的结构证据,而争议很多。本文中,我们对比了γ-Al_2O_3,SiO_2以及TiO_2三种不同载体上NiO分散后的结构。这些由EXAFS得到的直接结构证据,对于进一步阐述NiO催化剂的分散和作用机理以及筛选新的催化剂,显然是有意义的。
Finding an appropriate carrier and understanding the effect of the carrier on the dispersion of the active ingredient and the structure of the dispersed state have long been one of the most prominent tasks in catalytic industrial research and one of the most striking issues in catalytic theoretical research. Due to the failure to find a powerful means to directly observe the structural changes after dispersion of the active components in different supported catalysts, people have done a great deal of work for a long time, but so far the screening of the catalyst has not completely got rid of the “cooking ”Model, although some catalytic systems also put forward some carrier and catalyst mechanism of action model, the end result of the lack of direct structural evidence, and a lot of controversy. In this paper, we compared the structures of NiO dispersed on three different supports of γ-Al 2 O 3, SiO 2 and TiO 2. These direct structural evidences obtained by EXAFS are obviously of interest to further elucidate the dispersion and mechanism of action of NiO catalysts and to screen for new catalysts.