Ce-Fe-O mixed oxide as oxygen carrier for the direct partial oxidation of methane to syngas

The Ce-Fe-O mixed oxide with a ratio of Ce/Fe=7:3, which was prepared by coprecipitation method and employed as oxygen carrier, for direct partial oxidation of methane to syngas in the absence of gaseous oxygen was explored. The mixed oxide was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), and the catalytic performances were studied in a fixed-bed quartz reactor and a thermogravimetric reactor, respectively. Approximately 99.4% H2 selectivity, 98.8% CO selectivity and 94.9% CH4 conversion were achieved at 900 °C in fixed-bed experiments, furthermore, the increase of reaction temperature was favourable for the production of syngas. The results of thermal gravity cycle experiments showed that the Ce-Fe-O mixed oxide catalyst could complete five cycles in 10949 s in methane and air alternately atmosphere, and the catalyst regenerated with air has the same substance phase structure as the fresh when characterized by XRD. The SEM micrograph characterizations revealed that catalyst did not exhibit obvious agglomeration when exposed to alternating oxidizing and reducing atmosphere at a higher reaction temperature. In conclusion, the Ce-Fe-O mixed oxide as the oxygen carrier showed good activity and cycle performance. It was suggested that using lattice oxygen of Ce-Fe-O mixed oxide instead of gaseous oxygen to react with methane for production syngas is viable.