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Environmental TEM Investigation of Electrochemical Stability of Perovskite and Ruddlesden–Popper Type Manganite Oxygen Evolution Catalysts
Author(s) -
Mierwaldt Daniel,
Roddatis Vladimir,
Risch Marcel,
Scholz Julius,
Geppert Janis,
Abrishami Majid Ebrahimizadeh,
Jooss Christian
Publication year - 2017
Publication title -
advanced sustainable systems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.499
H-Index - 24
ISSN - 2366-7486
DOI - 10.1002/adsu.201700109
Subject(s) - oxygen evolution , perovskite (structure) , catalysis , ionic bonding , electrochemistry , materials science , manganite , chemical physics , chemical engineering , electrode , inorganic chemistry , chemistry , ion , crystallography , physics , organic chemistry , ferromagnetism , engineering , biochemistry , quantum mechanics
The sluggish kinetics of the oxygen evolution reaction (OER) is a grand challenge for energy storage technologies. Several perovskites and other oxides of earth‐abundant elements are found to exhibit improved catalytic OER activity. However, less attention is paid to the electrochemical stability, an important factor for large‐scale application. The ongoing search for stable catalysts calls for characterizing active catalyst surfaces and identifying mechanisms of deactivation, activation, or repair. In situ techniques are indispensable for these tasks. This study uses environmental transmission electron microscopy on the highly correlated perovskite Pr 1– x Ca x MnO 3 and the Ruddlesden–Popper Pr 0.5 Ca 1.5 MnO 4 as model electrodes to elucidate the underlying mechanisms of the stability trends identified on rotating ring disk electrodes. An electron beam at fluxes well below those that would cause radiation damage is used to induce positive local electrode potentials due to secondary electron emission, driving electrochemical reactions in H 2 O vapor. The stability of the model systems increases with increasing ionic character of the MnO bond, while more covalent bonds are prone to corrosion, which is triggered by formation of point defects in the oxygen sublattice.