Development and performance of CeO2 supported BaCoO3−δ perovskite for chemical looping steam methane reforming

Chemical looping steam methane reforming (CL-SMR) is a promising approach to co-production of syngas and hydrogen, and the reactivity of oxygen carriers is crucial in the performance of CL-SMR. In this study, CeO2 supported BaCoO3-δ oxygen carriers with different component distributions (labeled as dry-mix, sol-gel, co-sol-gel samples) were prepared and evaluated in CL-SMR. The BaCoO3-δ was loosely attached on CeO2 in the dry-mix sample, resulting in a high resistance to oxygen mobility and a low gas production. The co-sol-gel sample possessed impurities of Co3O4, BaCO3 and BaCeO3, which decreased reaction capacity and enhanced the secondary reaction of methane decomposition, leading to an excessive H2/CO ratio of syngas and coke formation. The contact of perovskite and CeO2 in sol-gel sample favors the synergistic effect of perovskite and CeO2, where the H2/CO ratio was close to the ideal value of 2 at 850 °C with the produced syngas and hydrogen reaching 4.57 mol/kg and 1.47 mol/kg, respectively. In situ Diffuse Reflectance Infrared Fourier Transform spectroscopy was employed to investigate the reaction mechanism of partial oxidation of methane, indicating that CH4 is gradually dehydrogenated and partially oxidized by lattice oxygen, and the conversion of -O-CH3 into -CHO and H2 is the rate-controlling step.