In situ X-ray probing reveals fingerprints of surface platinum oxide
- 9 November 2010
- journal article
- Published by Royal Society of Chemistry (RSC) in Physical Chemistry Chemical Physics
- Vol. 13 (1), 262-266
- https://doi.org/10.1039/c0cp01434f
Abstract
In situ X-ray absorption spectroscopy (XAS) at the Pt L3 edge is a useful probe for Pt–O interactions at polymer electrolyte membrane fuel cell (PEMFC) cathodes. We show that XAS using the high energy resolution fluorescence detection (HERFD) mode, applied to a well-defined monolayer Pt/Rh(111) sample where the bulk penetrating hard X-rays probe only surface Pt atoms, provides a unique sensitivity to structure and chemical bonding at the Pt-electrolyte interface. Ab initio multiple-scattering calculations using the FEFF code and complementary extended X-ray absorption fine structure (EXAFS) results indicate that the commonly observed large increase of the white-line at high electrochemical potentials on PEMFC cathodes originates from platinum oxide formation, whereas previously proposed chemisorbed oxygen-containing species merely give rise to subtle spectral changes.This publication has 41 references indexed in Scilit:
- Alloys of platinum and early transition metals as oxygen reduction electrocatalystsNature Chemistry, 2009
- Platinum monolayer electrocatalysts for oxygen reductionElectrochimica Acta, 2007
- Stabilization of Platinum Oxygen-Reduction Electrocatalysts Using Gold ClustersScience, 2007
- Determination of O and OH Adsorption Sites and Coverage in Situ on Pt Electrodes from Pt L23 X-ray Absorption SpectroscopyThe Journal of Physical Chemistry B, 2005
- Origin of the Overpotential for Oxygen Reduction at a Fuel-Cell CathodeThe Journal of Physical Chemistry B, 2004
- Platinum Monolayer Electrocatalysts for O2 Reduction: Pt Monolayer on Pd(111) and on Carbon-Supported Pd NanoparticlesThe Journal of Physical Chemistry B, 2004
- Effect of particle size on the electrocatalysis by carbon-supported Pt electrocatalysts: an in situ XAS investigationJournal of Electroanalytical Chemistry, 1998
- Role of Structural and Electronic Properties of Pt and Pt Alloys on Electrocatalysis of Oxygen Reduction: An In Situ XANES and EXAFS InvestigationJournal of the Electrochemical Society, 1995
- Quantitative technique for the determination of the number of unoccupied d-electron states in a platinum catalyst using the L2,3 x-ray absorption edge spectraThe Journal of Physical Chemistry, 1984
- Relationship between the area of L2,3 x-ray absorption edge resonances and the d orbital occupancy in compounds of platinum and iridiumThe Journal of Chemical Physics, 1982