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MM: Fachverband Metall- und Materialphysik
MM 35: Interfaces
MM 35.1: Talk
Wednesday, March 14, 2018, 11:45–12:00, H 0107
Strain-controlled electrocatalysis on gold thin film — •Xinyan Wu1, Matthias Graf2,3, and Jörg Weißmüller1,3 — 1Institute for Materials Physics and Technology, Hamburg University of Technology, Hamburg — 2Institute for Electronic and Optical Materials, Hamburg University of Technology, Hamburg — 3Insitute for Materials Technology, Helmholtz-Zentrum Geesthacht, Geesthacht
It is well known that the elastic deformation of a surface in its tangent plane modifies adsorption enthalpies. The observation is particularly relevant in heterogeneous catalysis, where strain - for instance in pseudomorphic active layers - is recognized as a means of tuning the reactivity and selectivity. Yet, quantifiable experimental observations of the impact of strain for catalysis are exceedingly rare. In other words, the field lacks a quantitative experimental database. Here, we use Dynamic Electro-Chemo-Mechanical Analysis (DECMA) in order to investigate the impact of strain on the electrocatalytic methanol oxidation on planar gold surfaces as a model reaction. Our approach works with a cyclic elastic strain applied to the surface and it detects modulations in the surface state and in the reaction current by means of a lock-in technique. In this way, DECMA affords quantifying the coupling between mechanics and reactivity as a function of the overpotential. In this way, the coupling strength can be explored separately for each reaction step.