Design and characterization by EXAFS, FTIR, and TEM of Rh-Sn/SiO{sub 2} catalysts active for NO-H{sub 2} reaction
- Univ. of Tokyo (Japan)
Rh-Sn/SiO{sub 2} catalysts, prepared by the selective reaction between Sn(CH{sub 3}){sub 4} and small Rh metallic particles supported on SiO{sub 2}, showed much higher catalytic activities for NO-H{sub 2}reaction and NO dissociation than Rh/SiO{sub 2} and coimpregnation Rh-Sn/SiO{sub 2}. In order to examine the important factors for the efficient catalysis of the Rh-Sn/SiO{sub 2} catalysts, the samples were characterized by Sn K- and Rh K-edge EXAFS, FTIR, H{sub 2} and Co adsorption, and TEM. For the Rh-Sn/SiO{sub 2} catalysts (Sn/Rh{ge}0.4), the surface concentration of Sn to Rh was estimated to be Sn{sub s}/Rh{sub s} = 3, where a Rh atom is surrounded by six Sn atoms. According to the results of the Sn K-edge EXAFS analysis, the bond distance between a Sn atom and the nearest-neighbor atom in the first layer atoms was 0.270 nm, and the bond distance between a Sn atom and a metal atom in the second layer was 0.290 nm, suggesting a relaxation of the first bimetallic layer. A surface model structure of Rh-Sn particles on SiO{sub 2} as a catalytically active bimetallic ensemble is discussed. 34 refs., 8 figs., 4 tabs.
- OSTI ID:
- 110978
- Journal Information:
- Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 1 Vol. 149; ISSN 0021-9517; ISSN JCTLA5
- Country of Publication:
- United States
- Language:
- English
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