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O: Fachverband Oberflächenphysik
O 30: Mini-Symposium: Electrified solid-liquid interfaces I
O 30.3: Talk
Tuesday, March 2, 2021, 11:45–12:00, R1
Ni(OH)2 modified Cu(111): interfacial water structure and electrocatalysis — •Andrea Auer1, Francisco J. Sarabia2, Daniel Winkler1, Victor Climent2, Juan Feliu2, and Julia Kunze-Liebhäuser1 — 1Institute of Physical Chemistry, University Innsbruck, Austria — 2Instituto Universitario de Electroquímica, Universidad de Alicante, Spain
The design of bimetallic electrodes is one key tactic to tune their activity and selectivity for electrocatalysis. Here, irreversible adsorption of Ni ions[1] was used to prepare Ni(OH)2 modified Cu(111) electrodes with different coverages and to study their effect on the hydrogen evolution reaction (HER) and CO reduction in alkaline media. To investigate the structure-activity relation, electrochemical scanning tunneling microscopy was performed and shows morphological changes upon modification consistent with adsorption of Ni(OH)2 on the step edges. The presence of Ni(OH)2 on Cu(111) leads to an enhancement in the rate of the HER, similar to Ni(OH)2/Pt(111) electrodes[1], but also changes the selectivity of the CO reduction. Intriguingly, laser induced temperature jump experiments reveal that the Ni(OH)2 modification influences the charge distribution at the interface by a decrease of the electric field strength. This implies an easier reorganization of the interfacial water molecules facilitating charge transfer through the double layer, and thus enhancing the electrocatalytic reaction.
[1] F. J. Sarabia, P. Sebastián-Pascual, M. T. M. Koper, V. Climent, J. M. Feliu, ACS Appl. Mater. Interfaces 2019, 11, 1, 613-623.