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Title: Unexpected compositional and structural modification of CoPt 3 nanoparticles by extensive surface purification

Abstract

We combined synchrotron small angle X-ray scattering, X-ray fluorescence and extended X-ray absorption fine structure spectroscopy to probe the structure of chemically synthesized CoPt 3 nanoparticles (NPs) after ligand removal via the commonly accepted solvent/nonsolvent approach. We showed that the improved catalytic activity of extensively purified NPs could not be explained only in terms of a “cleaner” surface. We found that extensive surface purification results in the substantial leaching of the Co atoms from the chemically synthesized CoPt 3 NPs transforming them into CoPt 3/Pt core/shell structures with an unexpectedly thick (~0.5 nm) Pt shell. We indicated that the improved catalytic activity of extensively purified NPs in octyne hydrogenation reaction can be explained by the formation of CoPt 3/Pt core/shell structures. Also, we demonstrated that drastic compositional and structural transformation of water transferred CoPt 3 NPs was rather a result of extensive removal of native ligands via a solvent/nonsolvent approach than leaching of cobalt atoms in aqueous media. We expect that these findings can be relevant to other transition metal based multicomponent NPs.

Authors:
ORCiD logo [1];  [2];  [1];  [1];  [2]; ORCiD logo [2];  [1]
  1. Univ. Nacional de La Plata, La Plata (Argentina). INIFTA, CONICET and Dpto. Química, Facultad de Ciencias Exactas
  2. Argonne National Lab. (ANL), Argonne, IL (United States). Center for Nanoscale Materials
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Scientific and Technical Research Council; Universidad Nacional de La Plata (UNLP); Laboratorio Nacional de Luz Sincrotron (LNLS)
OSTI Identifier:
1481421
Grant/Contract Number:  
AC02-06CH11357
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Nanoscale
Additional Journal Information:
Journal Volume: 10; Journal Issue: 14; Journal ID: ISSN 2040-3364
Publisher:
Royal Society of Chemistry
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY

Citation Formats

Mizrahi, Martín D., Krylova, Galyna, Giovanetti, Lisandro J., Ramallo-López, José M., Liu, Yuzi, Shevchenko, Elena V., and Requejo, Félix G. Unexpected compositional and structural modification of CoPt3 nanoparticles by extensive surface purification. United States: N. p., 2018. Web. doi:10.1039/c8nr00060c.
Mizrahi, Martín D., Krylova, Galyna, Giovanetti, Lisandro J., Ramallo-López, José M., Liu, Yuzi, Shevchenko, Elena V., & Requejo, Félix G. Unexpected compositional and structural modification of CoPt3 nanoparticles by extensive surface purification. United States. doi:10.1039/c8nr00060c.
Mizrahi, Martín D., Krylova, Galyna, Giovanetti, Lisandro J., Ramallo-López, José M., Liu, Yuzi, Shevchenko, Elena V., and Requejo, Félix G. Mon . "Unexpected compositional and structural modification of CoPt3 nanoparticles by extensive surface purification". United States. doi:10.1039/c8nr00060c. https://www.osti.gov/servlets/purl/1481421.
@article{osti_1481421,
title = {Unexpected compositional and structural modification of CoPt3 nanoparticles by extensive surface purification},
author = {Mizrahi, Martín D. and Krylova, Galyna and Giovanetti, Lisandro J. and Ramallo-López, José M. and Liu, Yuzi and Shevchenko, Elena V. and Requejo, Félix G.},
abstractNote = {We combined synchrotron small angle X-ray scattering, X-ray fluorescence and extended X-ray absorption fine structure spectroscopy to probe the structure of chemically synthesized CoPt3 nanoparticles (NPs) after ligand removal via the commonly accepted solvent/nonsolvent approach. We showed that the improved catalytic activity of extensively purified NPs could not be explained only in terms of a “cleaner” surface. We found that extensive surface purification results in the substantial leaching of the Co atoms from the chemically synthesized CoPt3 NPs transforming them into CoPt3/Pt core/shell structures with an unexpectedly thick (~0.5 nm) Pt shell. We indicated that the improved catalytic activity of extensively purified NPs in octyne hydrogenation reaction can be explained by the formation of CoPt3/Pt core/shell structures. Also, we demonstrated that drastic compositional and structural transformation of water transferred CoPt3 NPs was rather a result of extensive removal of native ligands via a solvent/nonsolvent approach than leaching of cobalt atoms in aqueous media. We expect that these findings can be relevant to other transition metal based multicomponent NPs.},
doi = {10.1039/c8nr00060c},
journal = {Nanoscale},
issn = {2040-3364},
number = 14,
volume = 10,
place = {United States},
year = {2018},
month = {2}
}

Journal Article:
Free Publicly Available Full Text
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Cited by: 2 works
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Figures / Tables:

Figure 1 Figure 1: TEM overview of 9.3 nm CoPt3 NPs (a); dark field STEM image (b) EDX mapping images obtained by acquiring EDX spectra including the Co L series (c) and Pt L series (d); the line-scans derived from elemental maps across 9.3 nm CoPt3 NPs (e); size histograms calculated basedmore » on analysis of 220 NPs (f).« less

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Works referenced in this record:

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    Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.