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O: Fachverband Oberflächenphysik
O 48: Poster Session IV: Surface dynamics II: Phase transitions and elementary processes
O 48.4: Poster
Tuesday, March 2, 2021, 13:30–15:30, P
Computational insights into the buried interface of silica-coated Pt electrocatalysts — •Alexander Urban — Department of Chemical Engineering, Columbia University, New York, NY 10027, USA
Semipermeable membranes are attractive as protective coatings for metal electrocatalysts in harsh environments, but their impact on the catalytic properties has not been fully understood. Experimentally probing buried membrane-catalyst interfaces in situ is challenging because standard surface-science techniques cannot be directly used.
Here, we discuss insights from first-principles modeling of silica-coated platinum electrocatalysts. We introduce the concept of interface Pourbaix diagrams to investigate the interaction of silica membranes with the surface of platinum metal electrocatalysts under different electrochemical conditions. The structure, composition, and adhesion energy of the buried SiO2/Pt interface depend on the pH value of the aqueous electrolyte and the electrode potential. Membrane-coating also affects the electronic structure of the catalyst surface, which has direct implications for the catalytic reactivity
Our analysis indicates that semipermeable membrane coatings are not passive bystanders but affect the properties of electrocatalysts, thereby offering as yet unexplored tuning knobs for the design of corrosion-stable electrocatalysts.