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Degradation of Bimetallic Model Electrocatalysts: An In Situ X-Ray Absorption Spectroscopy Study

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  • This work is supported by the Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under contract DE-AC02-76SF00515. This research was partly carried out at the Stanford Synchrotron Radiation Lightsource, a National User Facility operated by Stanford University on behalf of the U.S. Department of Energy, Office of Basic Energy Sciences.

Abstract

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Gold support destabilizes platinum: Driven by the low surface energy of Au, a Pt fuel cell catalyst is removed from the surface of the Au support. Depending on the electrochemical potential, this removal can occur through Pt dissolution either into the Au substrate or into the electrolyte (see picture). In situ HERFD XAS measurements indicate formation of PtO2 by a dissolution–precipitation mechanism.

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