摘要：

To assess the role of carbidic intermediates in hydrocarbon synthesis we have studied the incorporation of surface carbon into hydrocarbon products. To this end, supported transitionmetal catalysts (Ni, Co, and Ru) have been precovered with carbon, deposited via the Boudouard disproportionation of 13 CO. Subsequent exposure of these catalysts to 12 CO and H 2 led to the abundant production of 13 CH 4 and of hydrocarbons containing several 13 C atoms within one molecule. From this we conclude that oxygen-free species CH x ( x = 0 to 3) are possible intermediates in methanation and that they are capable of being incorporated into growing hydrocarbon chains. Our results suggest that in the Fischer-Tropsch synthesis CO dissociates in a fast step to give carbidic intermediates, from which both methane and the higher hydrocarbons are produced.

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