Oxidation of hydrocarbon fragments on metal single crystals and on supported metals

Results obtained on the reactions of hydrocarbon fragments (methylene, methyl, ethyl, propyl and butyl) with adsorbed oxygen on metal surfaces are summarized and discussed. Hydrocarbon species have been generated by the thermal and photo-induced dissociation of corresponding iodo compounds or by the pyrolysis of azomethane. Methods used are X-ray and ultraviolet photoelectron spectroscopy, high resolution electron energy loss spectroscopy and temperature programmed desorption. It is shown that adsorbed oxygen atoms readily combine with CxHy fragments above 150 K, and pathways of the oxidation sensitively depend on the nature of the metals. (C) 1998 Elsevier Science B.V.