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O: Fachverband Oberflächenphysik
O 21: Poster Session II: Solid-liquid interfaces: Reactions and electrochemistry I
O 21.1: Poster
Monday, March 1, 2021, 13:30–15:30, P
Stable and cost-efficient core-shell catalysts for enhanced acidic oxygen evolution–a first principles approach — •Yonghyuk Lee1,2, Christoph Scheurer1,2, and Karsten Reuter1,2 — 1Technical University Munich, Germany — 2Fritz-Haber-Institut der Max-Planck-Gesellschaft, Germany
Most commercial oxygen evolution reaction (OER) catalysts in proton exchange membrane electrolyzers contain precious IrO2 due to its high catalytic activity and favorable stability in acidic electrolytes. IrO2 supported on rutile TiO2 has been utilized in order to reduce the price without sacrificing activity. However, thin IrO2 films seem generally not stable on titania and a gradual dewetting of the film takes place.
In the present work, we use density-functional theory (DFT) calculations to further scrutinize the feasibility of encapsulating a cheap rutile TiO2 core with thin coherent IrO2 or RuO2 films as potentially stable catalyst materials for water electrolysis. We calculate facet-resolved interface formation energies and works of adhesion to quantify the effect of interfacial strain, the stability of the oxide interfaces and their strong directional dependence. A wetting tendency results only for some low-index facets under experimental gas-phase synthesis conditions. Surprisingly, ab initio thermodynamics indicates a significantly better wetting stability for lattice-matched RuO2 films in more oxidizing conditions such as under OER operation. The calculations also predict an enhanced OER activity of epitaxial RuO2/TiO2 core-shell particles. [1] D. Opalka et al., ACS Catal. 9, 4944 (2019).