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Regensburg 2013 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 44: Topical Session: TEM-Symposium - In-Situ II

MM 44.2: Topical Talk

Wednesday, March 13, 2013, 16:45–17:15, H25

In-situ environmental TEM studies of oxide electro-catalysts — •Christian Jooss1, Stephanie Raabe1, Daniel Mierwaldt1, Jim Ciston2, Matthé Uijttewaal3, Jörg Hoffmann1, Peter Blöchl3, and Yimei Zhu41Inst. of Materials Physics, University of Goettingen, Germany — 2National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, USA — 3Inst. of Theoretical Physics, Technical University of Clausthal, Germany — 4Dep. of Cond. Mat. Phys., Brookhaven National Laboratory, USA

In-situ studies of catalysts under operation conditions are of high scientific interest since their atomic and electronic structure in their active state may fundamentally differ from that in equilibrium. In addition, reactions in the vapor phase can hardly be observed. We present an in-situ ETEM study of electro-catalytic O2 evolution during H2O splitting based on Pr-doped CaMnO3 perovskite catalysts. This materials system offer the opportunity for studies of the role of correlation effects and mixed valence physics in multi-charge transfer catalysis. We observe changes in surface and subsurface structure as well as in Mn valence in the active state during O2 evolution. The electro-chemical processes can be controlled by application of a bias. For validation of the obtained results, the ETEM studies are complemented by in-situ X-ray absorption spectroscopy (XANES) and ex-situ cyclic voltammetry studies. This allows for deriving conclusions about the opportunities and challenges for controlled electro-chemical experiments in the ETEM. S. Raabe et al. Adv. Funct. Mater. 2012, DOI: 10.1002/adfm.201103173

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