The oxidative coupling of methane on lithium nickelate(III)

Abstract

Kinetic studies and isotopic exchange measurements (CH₄–CD₄ and ¹⁶O₂–¹⁸O₂) of the oxidative coupling of methane over stoichiometric LiNiO₂ indicate a redox mechanism involving lattice oxygen atoms. The formation of C₂ products is second-order in methane, both in the presence and absence of gaseous oxygen. Methane is dissociatively adsorbed on Ni³⁺—O^2– sites, and the rate-determining step is the coupling of adsorbed CH₃. Reduction of the catalyst by methane forms NiO, over which deep oxidation occurs. Adsorbed oxygen or gaseous oxygen is responsible for the deep oxidation.