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Reduction behavior of Rh-Sn/SiO2 bimetallic catalysts and its co oxidation activity

1995; Elsevier BV; Linguagem: Inglês

10.1016/s0167-2991(06)81428-x

2542-6613

Satoru Nishiyama, Ikuo Yamamoto, Masahiro Akemoto, Shigeru Tsuruya, Mitsuo Masai,

Catalysts for Methane Reforming

Reduction behavior of Rh-Sn on SiO2 was studied by temperature programmed reduction methods. During the reduction of Rh-Sn/SiO2 preoxidized, Rh oxide was reducible in the range of 370–440 K first, then the reduction of Sn oxide proceeded at a higher temperature up to 470 K. X-ray diffraction powder patterns indicates that the higher temperature than 673 K was required in order to obtain well-mixed Rh-Sn bimetallic system. The catalyst reduced at 673 and 773 K indicated the high activity for CO oxidation reaction at low reaction temperatures. These results indicate the reduction behavior in the following; Rh oxide was reduced first and metallic Rh was formed, then Sn oxide was reduced by the spillover hydrogen which was formed on the metallic Rh particles. Finally, bimetallic system of Rh and Sn, e.g. Rh-Sn alloy, was formed at the higher temperature than 673 K. The obtained bimetallic surface was markedly active for CO oxidation reaction.