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Thermodynamics and Hysteresis of Oxide Formation and Removal on Platinum (111) Surfaces

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journal contribution
posted on 20.02.2016 by Edward F. Holby, Jeff Greeley, Dane Morgan
Oxygen adsorption on Pt(111) has many implications for a wide range of technologies including PEM fuel cells. Using DFT, we have calculated the stable phases for oxygen on Pt(111) surfaces up to one monolayer of oxygen coverage. Our predicted stable phases are consistent with electrochemical measurements and are in agreement with Temkin/Frumkin isotherm conditions. We predict a new phase at one monolayer that suggests a simple mechanism for oxygen place-exchange to subsurface positions. Analysis of the phase diagram provides a possible explanation for the hysteresis observed in Pt cyclic voltammograms in aqueous environments.