The rate of reaction of methane with oxygen in the presence of a Li-doped MgO catalyst has been studied as a function of the partial pressures of CH4, O2 and CO2 in a well-mixed reaction system which is practically gradientless with respect to gas-phase concentrations. It is concluded that the rate determining step involves reaction of methane adsorbed on the catalyst surface with a di-atomic oxygen species. The adsorption of oxygen is relatively weak. Carbon dioxide acts as a poison for the reaction of methane with oxygen, this probably being caused by competitive adsorption on the sites where oxygen (and possibly also methane) adsorbs.
Roos, J. A., Korf, S. J., Veehof, R. H. J., van Ommen, J. G., & Ross, J. R. H. (1989). Kinetic and mechanistic aspects of the oxidative coupling of methane over a Li/MgO catalyst. Applied catalysis, 52(1), 131-145. https://doi.org/10.1016/S0166-9834(00)83377-1