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 crated are not stable but disappear either as a result of reaction with SiO2 to form Li2SiO2 or by the formation and subsequent loss of the volatile compoun 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.