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Electrochemical Degradation of Pt–Ni Nanocatalysts: An Identical Location Aberration-Corrected Scanning Transmission Electron Microscopy Study
journal contribution
posted on 2018-12-06, 00:00 authored by Somaye Rasouli, Deborah Myers, Nancy Kariuki, Kenji Higashida, Naotoshi Nakashima, Paulo FerreiraThe
evolution of Pt–Ni nanoparticles supported on amorphous
carbon is investigated before and after electrochemical potential
cycling (0.6–1.1 V), using aberration-corrected scanning transmission
electron microscopy (STEM) and energy dispersive X-ray spectroscopy
(EDS). During voltage cycling and due to the dissolution of
nanoparticles, single ions/atoms and ionic/atomic clusters emerge
and diffuse across the carbon support toward larger nanoparticles,
where they redeposit. We observe that the preferred locations for
the dissolution are the steps and corners of the nanoparticles. On
the other hand, the redeposition process happens often on {111} type
planes. In addition, contrary to the conventional view, where larger
particles grow isotropically from smaller ones, this research work
shows that anisotropic growth of smaller particles occurs during potential
cycling. The reason for this behavior seems to be related to the fact
that smaller particles with thicker Pt-rich shells trigger the nucleation
and deposition of Pt.
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Identical Location Aberration-Corrected Scanning Transmission Electron Microscopy Studyaberration-corrected scanning transmission electron microscopyredeposition processnanoparticlePt-rich shellsElectrochemical Degradationdissolutionresearch workanisotropic growthenergy dispersive X-ray spectroscopyvoltage cyclingEDScarbon support
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