title: Atomic structures and oxygen dynamics of CeO2 grain boundaries.
abstract: Material performance is significantly governed by grain boundaries (GBs), a typical crystal defects inside, which often exhibit unique properties due to the structural and chemical inhomogeneity. Here, it is reported direct atomic scale evidence that oxygen vacancies formed in the GBs can modify the local surface oxygen dynamics in CeO2, a key material for fuel cells. The atomic structures and oxygen vacancy concentrations in individual GBs are obtained by electron microscopy and theoretical calculations at atomic scale. Meanwhile, local GB oxygen reduction reactivity is measured by electrochemical strain microscopy. By combining these techniques, it is demonstrated that the GB electrochemical activities are affected by the oxygen vacancy concentrations, which is, on the other hand, determined by the local structural distortions at the GB core region. These results provide critical understanding of GB properties down to atomic scale, and new perspectives on the development strategies of high performance electrochemical devices for solid oxide fuel cells.
authors.affiliation: Institute of Engineering Innovation, The University of Tokyo, Tokyo 113-8656, Japan.
authors.forename: Bin
authors.initials: B
authors.lastname: Feng
authors.affiliation: Institute of Engineering Innovation, The University of Tokyo, Tokyo 113-8656, Japan.
authors.forename: Issei
authors.initials: I
authors.lastname: Sugiyama
authors.affiliation: Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama 226-8503, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Hojo
authors.affiliation: Research Institute for Electronic Science, Hokkaido University, Sapporo 001-0020, Japan.
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Ohta
authors.affiliation: Institute of Engineering Innovation, The University of Tokyo, Tokyo 113-8656, Japan.
authors.forename: Naoya
authors.initials: N
authors.lastname: Shibata
authors.affiliation: Institute of Engineering Innovation, The University of Tokyo, Tokyo 113-8656, Japan.|Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya 456-8587, Japan.|WPI advanced Institute for materials research, Tohoku University, Sendai 980-8577, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Ikuhara
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