The Final Stage Carbonaceous Deposits

This termed is frequently deployed in the literature to describe ill-defined and unwelcome substances deposited during hydrocarbon reactions on metals, leading to loss of catalytic activity. The work on hydrocarbon adsorption which we have reviewed has shown that, in almost every case, adsorbed species when heated decompose first to Ci species (e.g. =CH2 or H), and that these then lose their hydrogen atoms to form carbon atoms, which on Ir( 100) have been shown by LEED (and DFT) to reside in fourfold sites in a (2 x 2) overlayer. Further heating may lead to their polymerisation to graphite or to a diamond-like structure. Carbon 

Classics in Hydrocarbon Chemistry, WQey-VCH Chichester, 2000. 

Ponec and G.C. Bond, Catalysis by Metals and Alloys, Elsevier Amsterdam (1995). 

Catalysis by Metals, Academic Press London (1962). 

Yagasaki and R.l. Masel in Specialist Periodical Reports Catalysis, Vol. 11 (J.J. Spivey and 

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