有序Ce基催化剂的制备及CO催化氧化性能研究

发布时间：2018-06-27 15:08

本文选题：CO氧化 + CuO-CeO_2催化剂　；参考：《浙江师范大学》2016年硕士论文

【摘要】：众所周知,CO的催化氧化反应因为其重要的学术和实际应用价值在催化领域中占有举足轻重的地位,成为人们争相研究的热点。目前已有文献证明：催化剂的载体成分和表面的活性组分—金属物种的协同作用对CO催化氧化反应有很明显的促进作用。随着多孔材料的兴起和发展,我们将多孔材料的高比表面积、大孔容、发达的孔结构等优点应用于传统的CO催化氧化催化剂中,研究催化剂的形貌是否能对催化剂的活性有明显的提高作用。在本文中,我们利用PMMA(聚甲基丙烯酸甲酯)这种硬模板剂和三嵌段共聚物P123这种表面活性剂制备了一系列3DOMCuO-CeO_2催化剂(三维有序大孔CuO-CeO_2催化剂),并应用于CO催化氧化反应研究中。利用KIT-6为模板剂制备了PdO/meso-CeO_2和]meso-PdO-CeO_2两种催化剂。我们利用XRD, TEM, SEM, BET, H2-TPR, Raman, XPS以及原位FT-IR等表征方法对催化剂的结构等进行了表征；结合表征结果和活性数据阐述催化剂中金属与载体的协同作用以及多孔结构对反应的影响。本论文主要内容如下：1.利用PMMA作为硬模板剂和三嵌段共聚物P123作为表面活性剂制备了一系列具有三维有序大孔(3DOM)结构的CuO-CeO_2催化剂,分别考察了3DOMCuO-CeO_2催化剂中的CuO负载量和三维立体结构对CO催化氧化性能的影响。研究结果表明：当CuO负载量为20%时的20CuO-CeO_2-D催化活性最好,且催化活性明显优于通过等体积浸渍法制备的催化剂。这可能是由于三维有序大孔结构和三嵌段共聚物P123的使用大大提高了催化剂的比表面积,这有利于CuO颗粒在催化剂表面上分散度的提高。2.以KIT-6为模板剂,分别用不同的负载方法：“后负载法”和“一步法”制备出PdO/meso-CeO_2和]meso-PdO-CeO_2催化剂：用等体积浸渍法和溶胶凝胶法分别制备了PdO/CeO_2和PdO-CeO_2催化剂。结果表明：对于同种负载方法制备的催化剂,介孔结构催化剂活性较好；对于相同结构的催化剂,“后负载法”制备的催化剂活性明显高于通过“一步法”制备的催化剂,进一步说明在CO催化氧化反应中,起主要作用的是表面Pd及PdO物种,而不是Ce-Pd-O固溶体中的Pd~(n+)。
[Abstract]:It is well known that the catalytic oxidation of carbon monoxide (CO) plays an important role in the field of catalysis because of its important academic and practical application value. At present, it has been proved that the synergistic effect of the carrier composition and the active component on the surface of metal species has a significant effect on the catalytic oxidation of CO. With the rise and development of porous materials, the advantages of porous materials such as high specific surface area, large pore volume and developed pore structure are applied to the traditional catalysts for CO catalytic oxidation. Whether the morphology of the catalyst can improve the activity of the catalyst is studied. In this paper, a series of 3DOMCuO-CeO2 catalysts (three dimensional ordered macroporous CuO-CeO2 catalysts) have been prepared by using PMMA (polymethyl methacrylate), a hard template and triblock copolymer P123, which have been applied to the catalytic oxidation of CO. Two kinds of catalysts, PdO / meso-CeOs _ 2 and] meso-PdO-CeOS _ 2, were prepared by using KIT-6 as template. The structure of the catalyst was characterized by XRD, TEM, SEM, BET, H2-TPR, Raman, XPS and in situ FT-IR, and the synergistic effect of metal and support in the catalyst and the effect of porous structure on the reaction were described by combining the characterization results and the activity data. The main contents of this thesis are as follows: 1. A series of CuO-CeO _ 2 catalysts with three-dimensional ordered macroporous (3Dom) structure were prepared by using PMMA as hard template and triblock copolymer P123 as surfactant. The effects of CuO loading and three-dimensional structure on the catalytic oxidation of CO in 3DOMCuO-CeO2 catalyst were investigated. The results show that the catalytic activity of 20CuO-CeO2-D is the best when the CuO loading is 20 and the catalytic activity is obviously better than that prepared by the iso-volume impregnation method. This may be due to the use of three-dimensional ordered macroporous structure and triblock copolymer P123, which greatly improves the specific surface area of the catalyst, which is beneficial to the increase of the dispersion of CuO particles on the surface of the catalyst. Using KIT-6 as template, PdO / P / CEO _ 2 and] meso-PdO-CeO _ 2 catalysts were prepared by "post-loading method" and "one-step method", respectively. PdO _ (p-CeO _ (2) and PdO-CeO _ (2) catalysts were prepared by iso-volume impregnation method and sol-gel method, respectively. The results showed that the mesoporous structure catalyst had better activity for the same supported catalyst, and for the same structure catalyst, the activity of the catalyst prepared by "post-supported method" was obviously higher than that prepared by "one-step method". It is further indicated that PD and PDO species on the surface play a major role in CO catalytic oxidation, rather than PD ~ (n). In Ce-Pd-O solid solution.
【学位授予单位】：浙江师范大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O643.36

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