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O: Fachverband Oberflächenphysik
O 13: Solid-Liquid Interfaces I: Electrocatalysis and Photoelectrochemistry
O 13.1: Vortrag
Montag, 1. April 2019, 15:00–15:15, H16
Operando studies of well-defined Co oxide films for OER catalysis with surface X-ray diffraction — •Tim Wiegmann1,2, Finn Reikowski1, Firas Faisal4, Manon Bertram4, Jakub Drnec2, Fouad Maroun3, Jörg Libuda4, and Olaf Magnussen1 — 1Christian-Albrechts-Universität, 24118 Kiel, Germany — 2European Synchrotron Radiation Facility, 38000 Grenoble, France — 3Ecole Polytechnique, 91128 Palaiseau, France — 4Friedrich-Alexander-Universität, 91054 Erlangen, Germany
Transition metal oxides have recently received great attention as highly active, noble-metal-free catalysts for the oxygen evolution reaction (OER), which is a key reaction in electrochemical water splitting. To establish the relationship between their structure and catalytic activity, we conducted operando surface X-ray diffraction (XRD) studies on epitaxial Co3O4(111) thin films prepared by different methods. In addition to grazing incidence XRD, transmission surface XRD, a novel technique for fast capture of in-plane surface structure, was employed. For Co3O4 films electrodeposited as 3D islands on Au(111) and Au(100), a potential-dependent, reversible change of bulk lattice constant as well as the formation of a nm-thin skin layer can be observed over a wide potential range before the onset of OER. In comparison, smooth films grown in UHV on Ir(100) are structurally stable while exhibiting a much lower catalytic performance. The influence of the films’ granular morphology on their behaviour in the pseudo-capacitive regime and catalytic activity will be discussed.