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O: Fachverband Oberflächenphysik
O 67: Solid-Liquid Interfaces III: OER, ORR, CO2RR, etc.
O 67.4: Vortrag
Mittwoch, 18. März 2020, 11:30–11:45, WIL C107
Stable and cost-efficient core-shell catalysts for the electrochemical oxygen evolution reaction–a first-principles approach — •Yonghyuk Lee, Christoph Scheurer, and Karsten Reuter — Technical University Munich, Germany
Most commercial oxygen evolution reaction (OER) catalysts in proton exchange membrane electrolyzers contain expensive IrO2 due to its high catalytic activity and favorable stability in acidic electrolytes. Layer-coated IrO2 on rutile TiO2 has typically been utilized in order to reduce the price without sacrificing activity. However, thin IrO2 films are not thermally stable on titania and a gradual dewetting of the film takes place.
In the present work, we use density-functional theory (DFT) calculations to explore alternative core-shell systems. We assess IrO2 or RuO2 thin films on lattice-matched rutile oxides as potentially highly active, relatively inexpensive, and long-term stable catalyst materials for water electrolysis. We calculate interface energy, interface formation energy, and the work of adhesion to quantify the stability of the oxide interfaces and compare to the dewetting behavior of IrO2(110) films on TiO2(110). Ab initio thermodynamics and the computational hydrogen electrode model are employed to determine relative stabilities of the core-shell systems compared to pure rutile catalysts at OER operating conditions [1]. Finally, we present thermodynamic reaction barriers for potential anodic OER pathways at surfaces of these core-shell materials and discuss design strategies for next-generation electrocatalysts. [1] D. Opalka et al., ACS Catal. 9, 4944 (2019).