Direct methane oxidation on La1−xSrxCr1−yFeyO3−δ perovskite-type oxides as potential anode for intermediate temperature solid oxide fuel cells

• A series of La1−xSrxCr1−yFeyO3−δ perovskite-type oxides were synthesised.
• Direct methane oxidation was evaluated in different CH4-based gas mixtures.
• CH4 concentration affects kinetic of lattice oxygen ions release.
• H2S impurity in the fuel mixture leaves unaltered the methane oxidation reactions.
• C- and H-rich species are deposited on catalyst surface after methane exposure.

La1−xSrxCr1−yFeyO3−δ (x = 0, 0.1, 0.15, 0.2; y = 0, 0.3, 0.5) perovskite-type oxide powders were synthesized by solution combustion synthesis and characterized by X-ray diffraction, X-ray photoelectron spectroscopy and H2-temperature programmed reduction. Selected compositions were studied by CH4-temperature programmed reduction in the absence and in the presence of H2S. Temperature programmed oxidation and structural characterizations were performed in order to discriminate the nature of residual deposits on the catalyst surface. The study about reduction in different methane-based mixture revealed that total and partial methane oxidation occurred in the range ∼450–1000 °C independently of methane concentration. The H2S influence on methane oxidation was evaluated and experiments in CH4/H2S gas mixture indicated that La0.9Sr0.1Cr0.7Fe0.3O3−δ oxidized CH4 to CO2 and CO, as well as H2S to SO2. La0.9Sr0.1Cr0.7Fe0.3O3−δ was therefore identified a potential anode material for intermediate temperature solid oxide fuel cells directly fed with CH4 in the presence of H2S.

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