Publication: Direct observation of the dealloying process of a platinum–yttrium nanoparticle fuel cell cathode and its oxygenated species during the oxygen reduction reaction
Files
Program
KU-Authors
KU Authors
Co-Authors
Malacrida, Paolo
Casalongue, Hernan G. Sanchez
Masini, Federico
Hernandez-Fernandez, Patricia
Deiana, Davide
Ogasawara, Hirohito
Stephens, Ifan E. L.
Nilsson, Anders
Chorkendorff, Ib
Publication Date
Language
Type
Embargo Status
NO
Journal Title
Journal ISSN
Volume Title
Alternative Title
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.
Source
Publisher
Royal Society of Chemistry (RSC)
Subject
Physical chemistry, Physics
Citation
Has Part
Source
Physical Chemistry Chemical Physics
Book Series Title
Edition
DOI
10.1039/c5cp00283d