The oxygen reduction reaction (ORR) is one of the critical rate-limiting processes in many applications, including catalytic converters, oxygen-separation membranes, solid oxide fuel cells (SOFC), and batteries. Yet, a systematic understanding of the complex functional coupling between the catalytic reactions and surface states in transition metal oxides has not been achieved due to the lack of oriented single crystalline materials. Here, improved ORR kinetics are obtained in brownmillerite SrCoO2.5 films if the oxygen vacancy channels are oriented such that they reach the surface, rather than running parallel to it. This demonstrates that controlling the orientation of catalytically functional defects in cathode materials is a useful design strategy in the development of new materials for advanced energy technologies.
H. Jeen, Z. Bi, W. S. Choi, M. F. Chisholm, C. A. Bridges, M. P. Paranthaman, and H. N. Lee, “Orienting oxygen vacancies for fast catalytic reaction,” Advanced Materials DOI: 10.1002/adma.201302919.
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