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The catalytic performance of Mn/TiO_2,La-Mn/TiO_2,Li-La-Mn/TiO_2 etc for the oxidetive coupling of methane(OCM)was investignted.Thecatalysta were cheracterised with X-ray diffraction(XRD)and X-rayphotoelectron spectroscopy(XPS).The results reveal that catalyst Li-La-Mn/TiO_2 exhibits high activity and C_2 selectivity;Ti in this catalyst exists asTi~(+4) state;Li can promote the formation of lanthanum tituate via theinteraction between La and TiO_2;the formed La_2Ti_2O_7 and La_4Ti_9O_(24) aredistributed in the inner surface layer and Mn exists in outer surface layer in lowvalence states.The high activity and C_2 selectivity of catalyst Li-La-Mn/TiO_2are intimately related to the valence states of Mn,Li,La and theirdistribution on the catulyst surface layer.
The catalytic performance of Mn / TiO 2, La-Mn / TiO 2, Li-La-Mn / TiO 2 etc for the oxidetive coupling of methane (OCM) was investignted.The catalysta were cheracterised with X-ray diffraction (XRD) and X-rayphotoelectron spectroscopy (XPS). The results reveal that catalyst Li-La-Mn / TiO_2 exhibits high activity and C_2 selectivity; Ti in this catalyst exists as Ti ~ (+4) state; Li can promote the formation of lanthanum tituate via the interaction between La and TiO_2 The formed La_2Ti_2O_7 and La_4Ti_9O_ (24) aredistributed in the inner surface layer and Mn exists in outer surface layer in lowvalence states. The high activity and C_2 selectivity of catalyst Li-La-Mn / TiO_2are intimately related to the valence states of Mn, Li, La and theirdistribution on the catulyst surface layer.