Insights into the Oxygen Evolution Reaction of Oxide Catalysts Probed with Liquid-Phase TEM
Vasiliki Tileli a
a EPFL, Switzerland
Materials for Sustainable Development Conference (MATSUS)
Proceedings of Materials for Sustainable Development Conference (MAT-SUS) (NFM22)
#OPCAT - Operando Characterization of Electrocatalytic Interfaces
Barcelona, Spain, 2022 October 24th - 28th
Organizer: Reshma Rao
Invited Speaker, Vasiliki Tileli, presentation 161
DOI: https://doi.org/10.29363/nanoge.nfm.2022.161
Publication date: 11th July 2022

Surface and interface sensitive operando characterization methodologies are required to unlock electrochemical and electrocatalytic processes. Liquid phase electrochemical transmission electron microscopy (TEM) can provide the sensitivity and selectivity at single particle level. Herein, we investigate oxygen-evolving cobalt-based oxides in alkaline solution and we retrieve morphological, structural, chemical information during cyclic voltammetry measurement. We compare the highly active Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF) to the spinel Co3O4 and rocksalt CoO. The potential-dependent variation of the local contrast is associated to the modification of the wettability from hydrophobic to hydrophilic character at the oxide surfaces through interfacial capacitance phenomena. Molecular oxygen is probed in real-time during its evolution which results to further dewetting of the surfaces. Our work on catalysts exemplifies the crucial role that surface sensitive and electrochemical microcell TEM techniques can play in detailing the mechanism of electrocatalytic processes and can provide a new characterization framework aiding development of novel design routes for targeted catalyst preparation.

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