Development of BaSrCo-based perovskite for chemical-looping steam methane reforming: A study on synergistic effects of A-site elements and CeO2 support

Abstract Perovskite-type oxides could be applied for chemical looping steam methane reforming (CL-SMR) with a high selectivity in reacting with methane, but the reaction capacity is relative low. The supports with a high oxygen capacity could enhance the relative low reaction capacity of perovskite and improve the reaction selectivity. In this study, CeO 2 -supported Ba 1-x Sr x CoO 3-δ perovskite with different A-site doping ratios (x = 0, 0.1, 0.3, 0.5, 0.7, 0.9) were synthesized by sol-gel method, and the reactivity and cyclic performance of Ba 1-x Sr x CoO 3-δ /CeO 2 were analyzed. The Sr-doping Ba 1-x Sr x CoO 3-δ /CeO 2 oxygen carrier had a higher gas production than non-doping BaCoO 3-δ /CeO 2 , and the Ba 0.3 Sr 0.7 CoO 3-δ /CeO 2 showed the highest gas productions among the six samples. Sr-doping in A-site of perovskite increased the amounts of syngas and hydrogen, H 2 /CO ratio of syngas production was closed to the ideal value. XRD, XPS and FESEM were employed to investigate the physical and chemical properties of Ba 1-x Sr x CoO 3-δ /CeO 2 . The XRD results suggested that a part of CeO 2 reacted with A-site elements of perovskite and converted to BaCeO 3 and SrCeO 3. Ce ion reversibly shuttle between CeO 2 and ACeO 3 (A = Ba, Sr) depending on the local redox condition, this synergistic effect of A-site element and CeO 2 not only enhanced the selectivity of partial oxidizing of methane, but also increased the gas production of syngas and hydrogen compared with pure CeO 2 and Ba 1-x Sr x CoO 3-δ . XPS results indicated that lattice oxygen was the main oxygen source for syngas production. Moreover, Ba 1-x Sr x CoO 3-δ layer could get oxygen supply from CeO 2 and increase the gas production. FESEM showed that the uniformly adhered perovskite particles on the surface of CeO 2 could get more oxygen supply of CeO 2 to enhance gas productions; the slightly aggregation of Ba 1-x Sr x CoO 3-δ perovskite could enhance the oxygen mobility and improve the cyclic performance of Ba 1-x Sr x CoO 3-δ /CeO 2 .