Supported bimetallic catalysts have been shown to improve properties and catalytic performance of monometallic catalysts in various fuel conversion reactions. To investigate the effect of support on bimetallic PtCu system, PtCu supported on γ-Fe 2O 3 and CeO 2 were synthesized using electron beam irradiation method and preferential CO oxidation (PROX) performance was investigated in relation to structural and chemical properties of the catalysts. The difference in performance among the catalysts existed in both oxygen transport ability and selectivity. While oxygen transport ability was influenced by support property such as crystallite size (within the comparison among catalysts supported on CeO 2 and γ-Fe 2O 3), selectivity was rather influenced by support material which led to clear differences in reducibility, reduction degree of catalyst, and alloying extent of PtCu. CeO 2-supported catalysts are unique in the view point that they were able to convert CO selectively in high CO conversion region compared to Fe 2O 3-supported catalyst. PtCu with small CeO 2 crystallite maintained high O 2 conversion (high capacity for oxygen transport) in O 2-rich atmosphere in addition to high selectivity. Compared to monometallic Cu which lost its activity in the O 2-rich wet condition, or compared to monometallic Pt which exhibited poor selectivity, PtCu realized both high activity and selectivity on CeO 2 of small crystallite size, leading to more than 99% of CO conversion at 100°C. By modifying the structure, it was demonstrated that PtCu/CeO 2 system can be improved to have low-temperature activity comparable to monometallic Pt while keeping high selectivity of the original PtCu catalyst in the practical PROX condition.
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