Catalysis Today, Vol.24, No.3, 259-261, 1995
Study on the Oxidative Coupling of Methane - XRD and XPS Study of TiO2-Based Catalysts Promoted by Different Additives
The catalytic performance of Mn/TiO2, La-Mn/TiO2, Li-Mn/TiO2 and Li-La-Mn/TiO2 for the oxidative coupling of methane (OCM) was investigated. The catalysts were characterized with XRD and X-ray photoelectron spectroscopy (XPS). The results revealed that catalyst Li-La-Mn/TiO2 exhibited high activity and C-2 selectivity, Ti in this catalyst existed in the Ti(IV) state; Li could promote the formation of lanthanum titanate via the interaction of La and TiO2, the formed La2Ti2O7 and La-4 Ti9O24 distributed in the inner surface layer and Mn existed in the outer surface layer in low valence number. The high activity and C-2 selectivity of catalyst Li-La-Mn/TiO2 were intimately related to the valence number of Mn, Li, La and to their distribution on the catalyst surface layer.