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Title: How Ag Nanospheres Are Transformed into AgAu Nanocages

Abstract

Bimetallic hollow, porous noble metal nanoparticles are of broad interest for biomedical, optical and catalytic applications. The most straightforward method for preparing such structures involves the reaction between HAuCl 4 and well-formed Ag particles, typically spheres, cubes, or triangular prisms, yet the mechanism underlying their formation is poorly understood at the atomic scale. By combining in situ nanoscopic and atomic-scale characterization techniques (XAFS, SAXS, XRF, and electron microscopy) to follow the process, we elucidate a plausible reaction pathway for the conversion of citrate-capped Ag nanospheres to AgAu nanocages; importantly, the hollowing event cannot be explained by the nanoscale Kirkendall effect, nor by Galvanic exchange alone, two processes that have been previously proposed. We propose a modification of the bulk Galvanic exchange process that takes into account considerations that can only occur with nanoscale particles. In conclusion, this nanoscale Galvanic exchange process explains the novel morphological and chemical changes associated with the typically observed hollowing process.

Authors:
 [1];  [1];  [1];  [1]; ORCiD logo [1]; ORCiD logo [1]
  1. Northwestern Univ., Evanston, IL (United States)
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1393316
Alternate Identifier(s):
OSTI ID: 1408113
Grant/Contract Number:  
FG02-08ER46539
Resource Type:
Journal Article: Published Article
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 139; Journal Issue: 35; Journal ID: ISSN 0002-7863
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
ENGLISH
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Moreau, Liane M., Schurman, Charles A., Kewalramani, Sumit, Shahjamali, Mohammad M., Mirkin, Chad A., and Bedzyk, Michael J. How Ag Nanospheres Are Transformed into AgAu Nanocages. United States: N. p., 2017. Web. doi:10.1021/jacs.7b06724.
Moreau, Liane M., Schurman, Charles A., Kewalramani, Sumit, Shahjamali, Mohammad M., Mirkin, Chad A., & Bedzyk, Michael J. How Ag Nanospheres Are Transformed into AgAu Nanocages. United States. doi:10.1021/jacs.7b06724.
Moreau, Liane M., Schurman, Charles A., Kewalramani, Sumit, Shahjamali, Mohammad M., Mirkin, Chad A., and Bedzyk, Michael J. Fri . "How Ag Nanospheres Are Transformed into AgAu Nanocages". United States. doi:10.1021/jacs.7b06724.
@article{osti_1393316,
title = {How Ag Nanospheres Are Transformed into AgAu Nanocages},
author = {Moreau, Liane M. and Schurman, Charles A. and Kewalramani, Sumit and Shahjamali, Mohammad M. and Mirkin, Chad A. and Bedzyk, Michael J.},
abstractNote = {Bimetallic hollow, porous noble metal nanoparticles are of broad interest for biomedical, optical and catalytic applications. The most straightforward method for preparing such structures involves the reaction between HAuCl4 and well-formed Ag particles, typically spheres, cubes, or triangular prisms, yet the mechanism underlying their formation is poorly understood at the atomic scale. By combining in situ nanoscopic and atomic-scale characterization techniques (XAFS, SAXS, XRF, and electron microscopy) to follow the process, we elucidate a plausible reaction pathway for the conversion of citrate-capped Ag nanospheres to AgAu nanocages; importantly, the hollowing event cannot be explained by the nanoscale Kirkendall effect, nor by Galvanic exchange alone, two processes that have been previously proposed. We propose a modification of the bulk Galvanic exchange process that takes into account considerations that can only occur with nanoscale particles. In conclusion, this nanoscale Galvanic exchange process explains the novel morphological and chemical changes associated with the typically observed hollowing process.},
doi = {10.1021/jacs.7b06724},
journal = {Journal of the American Chemical Society},
number = 35,
volume = 139,
place = {United States},
year = {Fri Aug 11 00:00:00 EDT 2017},
month = {Fri Aug 11 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1021/jacs.7b06724

Citation Metrics:
Cited by: 10 works
Citation information provided by
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