Regensburg 2025 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 65: Solid-Liquid Interfaces: Reactions and Electrochemistry III

O 65.4: Vortrag

Mittwoch, 19. März 2025, 15:45–16:00, H6

Electrochemical XPS for probing the electrified solid-liquid interface of tungsten carbide — Christoph Griesser, Toni Moser, Sergio Diaz-Coello, and •Julia Kunze-Liebhäuser — Institute of Physical Chemistry, University of Innsbruck, Innsbruck, Austria

A profound understanding of the solid/liquid interface is central in electrochemistry and electrocatalysis, as the interfacial properties determine the electro-reactivity of the system. This study reveals the in-situ surface chemistry evolution of tungsten carbide (WC) powders during electrochemical polarization. WC is known for its platinum-like properties and its high activity towards the hydrogen evolution reaction (HER), but prone to passivation upon air or electrolyte exposure. It is found that the unpreventable surface passivation layer on WC dissolves into the electrolyte under HER conditions, which explains the typically measured high HER electrocatalytic activity of this compound material. The electrochemical (EC-)XPS data provide profound chemical understanding of the electrode/electrolyte interface during operation. This enables fundamental contribution to bottom-up electrocatalyst development, and thus to the advancement of energy conversion and storage technologies.

We thank the FWF for financial support within the Cluster of Excellence MECS.

Keywords: near ambient pressure XPS; in-situ analytics; interface chemistry; electrocatalysis