Measurement of kinetic isotope effects over methane coupling catalysts in the presence of carbon dioxide

摘要

Despite a decade of study, details of the mechanism of the catalytic oxidation of methane to C-2 hydrocarbons remain uncertain. The original proposal of Ito et al. (1) for Li/MgO catalysts was as follows (Li~+O~-) + CH_4 ->(Li~+OH~-) + CH_3 (1) CH_3 + CH_3 ->C_2H_6 (2) 2(LI~+OH~-)->(LI~+O~-) + Li~+() + H_2O (3) (Li~+O~(2-)) + Li~+() + 1/2O_2 -> 2(Li~+O~-)(4) with step (1) fast and (3) or (4) rate limiting (where () is a surface vacancy).