Model type investigations to study activation processes of solid state electrodes and development of aberration corrected in situ STEM (Scanning Electron Transmission Microscopy) for electrochemical investigations

• Applicant: Dr. Eva Mutoro
• Subject Area: Physical Chemistry of Solids and Surfaces, Material Characterisation
• Term: from 2010 to 2012
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 168267549

• Final Report Year: 2012

Final Report Abstract

In summary, epitaxial thin film model-type perovskite-based electrodes have been prepared (PLD) and studied in detail (EIS, ex situ: AFM, SEM, OM, XRD, XPS, TOF-SIMS, ICP-MS, STEM; in situ: HRXRD, APXPS, SPEM, STEM, ESM). The main findings are that (i) compositional and structural surface modifications can significantly change and enhance the oxygen surface exchange reaction, (ii) it is possible to electrochemically control the surface composition of perovskites reversibly, and (iii) close to operating conditions of SOFCs epitaxial thin films exhibit a different surface composition than bulk material which may explain their higher electrocatalytic activity.

Publications

• Oxygen Reduction Kinetics Enhancement on a Heterostructured Oxide Surface for Solid Oxide Fuel Cells, J. Phys. Chem. Lett., 2010, 1, 3149-3155
  E.J. Crumlin, E. Mutoro, SJ. Ahn, G.J. la O’, D. N. Leonard, A. Borisevich, M. D. Biegalski, H. M. Christen, Y. Shao-Horn
  
• Enhanced Oxygen Reduction Activity on Surface-Decorated Perovskite Thin Films for Solid Oxide Fuel Cells, Energy Environ. Sci., 2011, 4, 3689-3696
  E. Mutoro, E.J. Crumlin, M. Biegalski, H. Christen, Y. Shao-Horn
  
• Reversible Compositional Control of Oxide Surfaces by Electrochemical Potentials, J. Phys. Chem. Lett., 2012, 3, 40-44
  Eva Mutoro, Ethan J. Crumlin, Hendrik Pöpke, Bjoern Luerssen, Matteo Amati, Majid K. Abyaneh, Michael D. Biegalski, Hans M. Christen, Luca Gregoratti, Jürgen Janek, and Yang Shao-Horn
  (See online at https://doi.org/10.1021/jz201523y)
• Surface strontium enrichment on highly active perovskites for oxygen electrocatalysis in solid oxide fuel cells, Energy Environ. Sci., 2012, 5, 6081-6088
  Ethan J. Crumlin, Eva Mutoro, Zhi Liu, Michael, E. Grass, Michael D. Biegalski, Yueh-Lin Lee, Dane Morgan, Hans M. Christen, Hendrik Bluhm and Yang Shao-Horn