Design Principles of Perovskites for Thermochemical Oxygen Separation.

ABSTRACT: Separation and concentration of O2 from gas mixtures is central to several sustainable energy technologies, such as solar-driven synthesis of liquid hydrocarbon fuels from CO2 , H2 O, and concentrated sunlight. We introduce a rationale for designing metal oxide redox materials for oxygen separation through "thermochemical pumping" of O2 against a pO2 gradient with low-grade process heat. Electronic structure calculations show that the activity of O vacancies in metal oxides pinpoints the ideal oxygen exchange capacity of perovskites. Thermogravimetric analysis and high-temperature X-ray diffraction for SrCoO3-? , BaCoO3-? and BaMnO3-? perovskites and Ag2 O and Cu2 O references confirm the predicted performance of SrCoO3-? , which surpasses the performance of state-of-the-art Cu2 O at these conditions with an oxygen exchange capacity of 44?mmol?O?2?mol?SrCoO?3-?(-1) exchanged at 12.1??mol?O?2?min(-1) ?g(-1) at 600-900?K. The redox trends are understood due to lattice expansion and electronic charge transfer.

SUBMITTER: Ezbiri M 

PROVIDER: S-EPMC4831027 | biostudies-literature | 2015 Jun

REPOSITORIES: biostudies-literature