The Effect of Exposed Facets of Ceria to the Nickel Species in Nickel-Ceria Catalysts and Their Performance in a NO + CO Reaction

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• 作者：Ke Tang ; Wei Liu ; Jing Li ; Jinxin Guo ; Jingcai Zhang ; Shuping Wang ; Shengli Niu ; Yanzhao Yang
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：December 9, 2015
• 年：2015
• 卷：7
• 期：48
• 页码：26839-26849
• 全文大小：655K
• ISSN：1944-8252

文摘

CeO₂ rods with {110} facets and cubes with {100} facets were utilized as catalyst supports to probe the effect of crystallographic facets on the nickel species and the structure-dependent catalytic performance. Various analysis methods (ex and in situ XRD, TEM, Raman, XPS, TPR, TPD) were used to investigate the structural forms of the catalysts, and these results indicated that the deposition of nickel species resulted in the formation of two main active types of the catalyst components: NiO strongly or weakly interacted with the surface and Ni鈥揅e鈥揙 solid solution. Notably, the states and distribution ratio of nickel species were related to the shape of CeO₂. It was found that CeO₂ rods had more active sites to coordinate with nickel species to form a strong interaction with NiO on the surface and a more stable construction when compared to cubes. Furthermore, the nickel-ceria catalysts with rod shape were more active towards NO oxidation with complete conversion below 191 掳C, but for cube shape, complete conversion occurred above 229 掳C (e.g., for nickel loading of 鈭?%, the complete conversion temperature was 154 掳C for the rod shape and 229 掳C for the cube shape). On the basis of the analysis of the catalysts structure, the superior catalytic activity was due to a combination of surface structures of NiO (mainly strongly interacting with the surface) and nickel ions Ni²⁺ in the Ni鈥揅e鈥揙 bulk phase.