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Ruthenium-thoria catalysts, prepared either by oxidation of Ru3Th7 intermetallic or impregnation of high surface area Th02 with Ru(N0)(N03)3, were characterized by ESCA, ISS, X-ray diffraction (XRD), chemisorption, and gravimetric measurements. XRD and gravimetric analysis indicated that the intermetallic was extensively decomposed by oxidation at 350 °C. ESCA and ISS Ru/Th intensity ratios for the intermetallic-derived catalyst were significantly lower than those obtained for the supported catalyst. This suggests a relative surface enrichment of Th in the alloy-derived catalyst. The catalysts were tested for CO hydrogenation. The turnover frequency of the catalyst derived from Ru3Th7 was 2 orders of magnitude higher than that of the catalyst prepared by impregnation. Exceptionally high methane selectivity was observed for the intermetallic-derived catalyst. The activity and selectivity data are discussed in terms of the reported structure sensitivity of the CO hydrogenation reaction and the differences in surface structures between the two types of catalysts.

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