In Situ Quantification of the Local Electrocatalytic Activity via Electrochemical Scanning Tunneling Microscopy.

Autor: Haid RW; Department of Physics (ECS), Technical University of Munich, James-Franck-Straße 1, Garching, 85748, Germany., Kluge RM; Department of Physics (ECS), Technical University of Munich, James-Franck-Straße 1, Garching, 85748, Germany., Liang Y; Department of Physics (ECS), Technical University of Munich, James-Franck-Straße 1, Garching, 85748, Germany., Bandarenka AS; Department of Physics (ECS), Technical University of Munich, James-Franck-Straße 1, Garching, 85748, Germany.; Catalysis Research Center TUM, Ernst-Otto-Fischer-Straße 1, Garching, 85748, Germany.
Jazyk: angličtina
Zdroj: Small methods [Small Methods] 2021 Feb; Vol. 5 (2), pp. e2000710. Date of Electronic Publication: 2020 Sep 29.
DOI: 10.1002/smtd.202000710
Abstrakt: Identification of catalytically active sites at solid/liquid interfaces under reaction conditions is an essential task to improve the catalyst design for sustainable energy devices. Electrochemical scanning tunneling microscopy (EC-STM) combines the control of the surface reactions with imaging on a nanoscale. When performing EC-STM under reaction conditions, the recorded analytical signal shows higher fluctuations (noise) at active sites compared to non-active sites (noise-EC-STM or n-EC-STM). In the past, this approach has been proven as a valid tool to identify the location of active sites. In this work, the authors show that this method can be extended to obtain quantitative information of the local activity. For the platinum(111) surface under oxygen reduction reaction conditions, a linear relationship between the STM noise level and a measure of reactivity, the turn-over frequency is found. Since it is known that the most active sites for this system are located at concave sites, the method has been applied to quantify the activity at steps. The obtained activity enhancement factors appeared to be in good agreement with the literature. Thus, n-EC-STM is a powerful method not only to in situ identify the location of active sites but also to determine and compare local reactivity.
(© 2020 The Authors. Published by Wiley-VCH GmbH.)
Databáze: MEDLINE
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