Ag supported on meso-structured SiO2 with different morphologies for CO oxidation: On the inherent factors influencing the activity of Ag catalysts
Ag supported on meso-structured SiO2 with different morphologies for CO oxidation: On the inherent factors influencing the activity of Ag catalysts
复制标题
不同形貌介观结构SiO2负载Ag用于CO氧化：影响Ag催化剂活性的内在因素
DOI：
10.1016/j.micromeso.2017.01.016
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发表时间：
2017
影响因子：
5.2
通讯作者：
Wang Xiang
中科院分区：
文献类型：
--
作者：
Xu Juan;Zhang Jingyan;Peng Honggen;Xu Xianglan;Liu Wenming;Wang Zheng;Zhang Ning;Wang Xiang
为了制备更好的CO氧化催化剂，并探索决定负载型Ag催化剂活性的内在因素，合成了一系列不同形貌的介孔SiO2KCC-1、SBA-15和MCM-41，并将其用作Ag的载体，制备了CO氧化催化剂（7%Ag/KCC-1、7%Ag/SBA-15和7%Ag/MCM-41）。 XRD和H2吸附-脱附结果表明，SiO2载体的形貌影响负载Ag物种的分散，从而导致催化剂具有不同的Ag晶粒尺寸和活性金属表面积。以纤维状KCC-1二氧化硅球为载体，开放的表面介孔可以有效地阻碍银颗粒的动员和聚集。因此，与SBA-15和MCM-41相比，获得了晶粒尺寸小得多的Ag纳米粒子，从而使催化剂的活性显着提高。此外，还发现 CO 氧化速率差异与 Ag 晶粒尺寸之间存在线性关系。因此，可以得出结论，活性银金属表面积是二氧化硅负载银催化剂活性的决定因素。
With the objective to prepare better CO oxidation catalysts and explore the inherent factors to determine the activity of supported Ag catalysts, KCC-1, SBA-15 and MCM-41, a series of mesoporous SiO2with different morphologies, have been synthesized and used as supports for Ag to prepare catalysts (7% Ag/KCC-1, 7% Ag/SBA-15 and 7% Ag/MCM-41) for CO oxidation. It is found that the morphologies of the SiO2supports influence the dispersion of the supported Ag species, thus resulting in catalysts with different Ag grain sizes and active metallic surface areas, as proved by XRD and H2adsorption-desorption results. With fibrous KCC-1 silica spheres as the support, the mobilization and aggregation of the Ag particles can be effectively hindered by the open access surface mesopores. Therefore, compared with SBA-15 and MCM-41, Ag nanoparticles with much smaller grain sizes have been achieved, thus resulting in a catalyst with significantly improved activity. Furthermore, a linear relationship has been found between the differential CO oxidation rates and the Ag grain size. Therefore, it is concluded that the active Ag metal surface area is the determining factor for the activity of the silica supported Ag catalysts.