FORMATION OF METHYLENE INTERMEDIATES BY HYDROGENATION OF SURFACE CARBON ON RU(001)
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Adsorbed methyne (CH) intermediates were synthesized on the Ru(001) surface by hydrogenation of predeposited carbon under UHV conditions. These species were identified by High-Resolution Electron Energy-Loss Spectroscopy (HREELS) based upon spectra which exhibited an intense CH stretch at 2950 cm-1 and no evidence for CH2 scissor or CH3 umbrella modes. The adsorbed CH species could be formed by hydrogenation of carbon initially deposited by electron-beam-stimulated dissociation of CO, by thermal decomposition of ethylene, or by ethylene hydrogenolysis. The maximum intensity of the CH stretch was observed for surface temperatures of 370 K; the CH species decomposed completely to H2 plus adsorbed carbon upon heating the surface to 500 K. These results are consistent with the participation of CH intermediates in the Fischer-Tropsch synthesis via the "active-carbide" mechanism. 1985.