Hydrogenated graphite

The formation of several volatile carbon hydrides in the hydrogen-graphite reaction between 360 and 800° was reported by Breisacher and Marx (138). The formation of ethane, ethylene, propylene, and even butane suggests that the edge of the carbon layers became hydrogenated in the first step of this reaction. The results were discussed on the basis of a mechanism proposal by Zielke and Gorin (139). 

G. Majer, E. Stanik, S. Orimo, NMR studies of hydrogen motion in nanostructured hydrogen-graphite systems. J. Alloys Compd., 356-357 (2003) 617-621. 

The standard enthalpy of formation of a compound, AHf, is defined as the increment in enthalpy associated with the reaction of forming a given compound from its elements, with each substance in its thermodynamic standard state at the given temperature.2 The thermodynamic cycle for the enthalpy of formation of methane (CH4) from the standard states of carbon and hydrogen (graphite and hydrogen molecules) is shown in Figure 1. 

These two effects of atomic hydrogen, graphite removal and sp bond stabilization, are believed essential to the growth of CVD diamond. 

Ogata, H., Miyajima, S., Matsutsnji, K., and Enoki, T. NMR stndy of sodimn-hydrogen-graphite ternary intercalation componnd. 

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