A molten carbonate shell modified perovskite redox catalyst for anaerobic oxidative dehydrogenation of ethane

Acceptor-doped, redox-active perovskite oxides such as La(0.8)Sr(0.2)FeO(3) (LSF) are active for ethane oxidation to CO(x) but show poor selectivity to ethylene. This article reports molten Li(2)CO(3) as an effective “promoter” to modify LSF for chemical looping–oxidative dehydrogenation (CL-ODH) of ethane. Under the working state, the redox catalyst is composed of a molten Li(2)CO(3) layer covering the solid LSF substrate. The molten layer facilitates the transport of active peroxide (O(2)(2−)) species formed on LSF while blocking the nonselective sites. Spectroscopy measurements and density functional theory calculations indicate that Fe(4+)→Fe(3+) transition is responsible for the peroxide formation, which results in both exothermic ODH and air reoxidation steps. With >90% ethylene selectivity, up to 59% ethylene yield, and favorable heat of reactions, the core-shell redox catalyst has an excellent potential to be effective for intensified ethane conversion. The mechanistic findings also provide a generalized approach for designing CL-ODH redox catalysts.