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Electrochemical Degradation of Pt–Ni Nanocatalysts: An Identical Location Aberration-Corrected Scanning Transmission Electron Microscopy Study

By Somaye Rasouli (6102113), Deborah Myers (1327362), Nancy Kariuki (2644942), Kenji Higashida (6102116), Naotoshi Nakashima (1498924) and Paulo Ferreira (3425282)

Abstract

The 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

Topics: Biophysics, Medicine, Cell Biology, Biotechnology, Ecology, Developmental Biology, Infectious Diseases, Biological Sciences not elsewhere classified, Chemical Sciences not elsewhere classified, Physical Sciences not elsewhere classified, Identical Location Aberration-Corrected Scanning Transmission Electron Microscopy Study, aberration-corrected scanning transmission electron microscopy, redeposition process, nanoparticle, Pt-rich shells, Electrochemical Degradation, dissolution, research work, anisotropic growth, energy dispersive X-ray spectroscopy, voltage cycling, EDS, carbon support
Year: 2018
DOI identifier: 10.1021/acs.nanolett.8b03022.s001
OAI identifier: oai:figshare.com:article/7485233
Provided by: FigShare
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