Ce-Doped La2O3 based catalyst for the oxidative coupling of methane

• Ce-doped La2O3 were prepared by citrate method and solvothermal method at 800 °C.
• The preparation method affected the type of oxygen species on the catalyst surface.
• The concentration of Ce3 + in ceria was associated with the ratio of oxygen species (O― + O22―) to lattice oxygen.

The effect of ceria was studied on the oxidative coupling of methane (OCM) with Ce-doped La2O3 in a La:Ce molar ratio of 75:25 using two preparation methods. The characterisation techniques used were XRD and XPS. The results revealed high concentration of oxygen vacancies. Different types of ions (Ce3 + + Ce4 +) were detected. More surface Ce3 + and higher ratio [(O22― + O—)/ O2―] were obtained in the oxide synthesised by the solvothermal method, affecting the OCM reaction in terms of higher C2 hydrocarbons selectivity. This was ascribed to the higher relative amount of O― species on the catalyst surface.

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