Ru, Ru-Fe and Fe films have been prepared in u.h.v. conditions. In temperature-programmed desorption experiments (t.p.d.) a reasonable desorption rate for both H2 and CO at ca. 550 K (the reaction temperature for the CO + H2 reaction) was observed only for Ru films, especially when the gases were adsorbed at 673 K and cooled to 300 K in H2 and CO, respectively. CO2 formation was observed in t.p.d. only, when large amounts of H2O were present. CH4 was the only product in the CO + H2 reaction at 10 Pa pressure on Ru. On Ru film surface carbon deposited by the dissociation of CH4 or CO could readily be hydrogenated to CH4. A mechanism for the CO + H2 reaction is proposed in which chemisorbed CO having a very weak bond between the carbon and oxygen atoms reacts with hydrogen, resulting in surface carbon and H2O. CH4 forms only in the next hydrogenation step. Iron and ruthenium-iron films, the latter being enriched in iron, proved to be completely inactive in this reaction. A possible explanation is given.
|Number of pages||12|
|Journal||Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases|
|Publication status||Published - Jan 1 1982|
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