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O: Fachverband Oberflächenphysik
O 21: Poster Session II: Solid-liquid interfaces: Reactions and electrochemistry I
O 21.8: Poster
Monday, March 1, 2021, 13:30–15:30, P
Boosting Hydrogen Evolution Reaction Activity by Lateral Electrode Structuring — •Thomas L. Maier1, Matthias Golibrzuch2, Tina Angerer1, Markus Becherer2, and Katharina Krischer1 — 1Nonequilibrium Chemical Physics, Technical University of Munich, Garching, Germany — 2Nanoelectronics, Technical University of Munich, Munich, Germany
Producing solar fuels with devices based on metal-insulator-semiconductor (MIS) interfaces is a very promising future technology for a renewable energy economy. The semiconductor part of such hybrid devices can provide efficient light absorption while the metal part facilitates fast reaction kinetics. However, in order to fulfil these two functionalities, the device requires patterning of the MIS interface.
We show that lateral structuring of silicon-based electrodes with well-defined gold arrays exhibits cooperative effects, i.e. strongly altered catalytic activities compared to bare metal surfaces. We demonstrate this with the hydrogen evolution reaction (HER) in acidic and alkaline medium and show that the HER rate scales with the interfacial area between the metal catalyst and the adjacent silicon oxide support. The rate of alkaline HER can be enhanced by an order of magnitude, which results in a very similar HER activity in alkaline and acidic medium. We explain this increase by a bifunctional mechanism at the metal/silicon oxide interface and argue that the lateral structuring changes locally the electric field, which increases the reaction rate of alkaline HER at the interface compared to the rate at the metal bulk.