Abstract
Oxygen dissociation on metal oxides is a key reaction step, limiting the efficiency of numerous technologies. The complexity of the multi-step oxygen reduction reaction (ORR) makes it difficult to investigate the oxygen dissociation step independently. Direct observation of the oxygen dissociation process is described, quantitatively, on perovskites La0.6 Sr0.4 Co0.2 Fe0.8 O3-δ and (La0.8 Sr0.2 )0.95 MnO3±δ , using gas-phase isotope-exchange with a 1:1 16 O2 :18 O2 ratio. Oxygen transport mechanisms between gas-surface reactions and surface-bulk exchange are deconvoluted. Our findings show that regardless of participation of lattice oxygen, La0.6 Sr0.4 Co0.2 Fe0.8 O3-δ is better at oxygen dissociation than (La0.8 Sr0.2 )0.95 MnO3±δ . Heteroexchange, involving lattice oxygen, dominates on La0.6 Sr0.4 Co0.2 Fe0.8 O3-δ . In contrast, (La0.8 Sr0.2 )0.95 MnO3±δ shows both homoexchange and heteroexchange, with the latter only happening above 600 °C. Using a 1:1 isotope mixture, a simple method is presented for separation of the oxygen dissociation step from the overall ORR.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
