La1-xSrxFeO3 perovskites as oxygen carriers for the partial oxidation of methane to syngas

We prepared perovskite-type oxides La1-xSrxFeO3 (x = 0, 0.3, 0.5, 0.9) by a combustion method and used these as oxygen carriers for the partial oxidation of methane. X-ray diffration, scanning electron microscopy and H2 temperature-programmed reduction techniques were used to characterize the samples. Their reduction and oxidation activities were investigated using a thermogravimetric analysis reactor and fixed-bed reaction equipment, respectively. The results showed that the lattice oxygen in La1-xSrxFeO3 was suitable for the partial oxidation of methane to produce syngas. Their capacity to provide oxygen was enhanced by the partial substitution of La3+ by Sr2+ and the synthesized materials have good regenerability. The optimal degree of Sr substitution was found to be x = 0.3–0.5 for La1-xSrxFeO3 with regard to reactivity, selectivity, and oxygen-donating ability. CH4 conversion was higher than 70%, and the n(H2)/n(CO) ratio remained about 2:1 and no obvious decomposition of CH4 occurred.

Graphical AbstractThe lattice oxygen in La1-xSrxFeO3 is suitable for the production of syngas by the partial oxidization of methane. La0.7Sr0.3FeO3 and La0.5Sr0.5FeO3 were found to be the best for CH4 conversion, the n(H2)/n(CO) ratio, and for selectivity toward H2 and CO.Figure optionsDownload as PowerPoint slide