Journal Article

FZJ-2021-02603

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png The Crucial Role of Water in the Stability and Electrocatalytic Activity of Pt Electrodes

Ranninger, J. (Corresponding author)FZJ* ; Mayrhofer, K. J. J.FZJ* ; Berkes, B. B.FZJ*

2021
Soc. Washington, DC

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Please use a persistent id in citations: http://hdl.handle.net/2128/28175  doi:10.1021/acs.jpcc.1c02124

Abstract: Understanding the role of water in the activity and stability of electrocatalysts is of great interest for different fundamental reactions. Investigations aiming to expand understanding of this are very challenging in aqueous electrolytes. By contrast, nonaqueous electrolytes with very well-defined water content can provide ideal conditions to better clarify the role of water in electrochemical reactions. In this paper, the dissolution and electrochemical behavior of Pt during potentiodynamic and potentiostatic measurements in methanol- and acetonitrile-based electrolytes with accurately controlled water content of <1 ppm, 100 ppm, 1000 ppm, 1%, and 10% are studied. In methanol-based electrolytes, we demonstrate the promoting effect of small amounts of water on the methanol oxidation reaction. We show the formation of surface oxide species with increasing water content in the Pt dissolution profile, which develops from a purely anodic to a predominantly cathodic dissolution, a known characteristic of aqueous electrolytes. The effect of water on the electrode stability is fundamentally different in acetonitrile-based systems: presumably, the strong adsorption of solvent molecules competes with the adsorption of water and thus inhibits the formation of an oxide layer at the surface even up to a water concentration of 1% as revealed by potentiodynamic measurements.

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Contributing Institute(s):

1. Helmholtz-Institut Erlangen-Nürnberg Erneuerbare Energien (IEK-11)

Research Program(s):

1. 123 - Chemische Energieträger (POF4-123) (POF4-123)

Appears in the scientific report 2021

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Database coverage:
; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Essential Science Indicators ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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