Oxidative coupling of methane over lithium doped magnesium oxide catalysts

Active sites are created on the surface of a Li/MgO catalyst used for the selective oxidation of methane, by the gradual loss of CO₂ from surface lithium carbonate species in the presence of oxygen. The sites created are not stable but disappear either as a result of reaction with SiO₂ to form Li₂SiO₃ or by the formation and subsequent loss of the volatile compound LiOH. The deactivation can be reversed, at least partially, by treating the catalyst in CO₂ under reaction conditions; it can be retarded if low concentrations of CO₂ are added to the reaction mixture.