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Issue 42, 2015
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Direct observation of the dealloying process of a platinum–yttrium nanoparticle fuel cell cathode and its oxygenated species during the oxygen reduction reaction

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Abstract

Size-selected 9 nm PtxY nanoparticles have recently shown an outstanding catalytic activity for the oxygen reduction reaction, representing a promising cathode catalyst for proton exchange membrane fuel cells (PEMFCs). Studying their electrochemical dealloying is a fundamental step towards the understanding of both their activity and stability. Herein, size-selected 9 nm PtxY nanoparticles have been deposited on the cathode side of a PEMFC specifically designed for in situ ambient pressure X-ray photoelectron spectroscopy (APXPS). The dealloying mechanism was followed in situ for the first time. It proceeds through the progressive oxidation of alloyed Y atoms, soon leading to the accumulation of Y3+ cations at the cathode. Acid leaching with sulfuric acid is capable of accelerating the dealloying process and removing these Y3+ cations which might cause long term degradation of the membrane. The use of APXPS under near operating conditions allowed observing the population of oxygenated surface species as a function of the electrochemical potential. Similar to the case of pure Pt nanoparticles, non-hydrated hydroxide plays a key role in the ORR catalytic process.

Graphical abstract: Direct observation of the dealloying process of a platinum–yttrium nanoparticle fuel cell cathode and its oxygenated species during the oxygen reduction reaction

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Article information


Submitted
16 Jan 2015
Accepted
04 Mar 2015
First published
13 Mar 2015

Phys. Chem. Chem. Phys., 2015,17, 28121-28128
Article type
Paper
Author version available

Direct observation of the dealloying process of a platinum–yttrium nanoparticle fuel cell cathode and its oxygenated species during the oxygen reduction reaction

P. Malacrida, H. G. Sanchez Casalongue, F. Masini, S. Kaya, P. Hernández-Fernández, D. Deiana, H. Ogasawara, I. E. L. Stephens, A. Nilsson and I. Chorkendorff, Phys. Chem. Chem. Phys., 2015, 17, 28121
DOI: 10.1039/C5CP00283D

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