Direct observation of the dealloying process of a platinum–yttrium nanoparticle fuel cell cathode and its oxygenated species during the oxygen reduction reaction
Research output: Research - peer-review › Journal article – Annual report year: 2015
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 nderstanding
of both their activity and stability. Herein, size-selected 9 nm PtxY anoparticles 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.
Original language | English |
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Journal | Physical Chemistry Chemical Physics |
Volume | 17 |
Issue number | 42 |
Pages (from-to) | 28121-28128 |
Number of pages | 8 |
ISSN | 1463-9076 |
DOIs | |
State | Published - 2015 |
Citations | Web of Science® Times Cited: 21 |
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