Morphological evolution of Pt-modified nanoporous gold after thermal coarsening in reductive and oxidative environments

Abstract Nanoporous gold made by dealloying AgAuPt (NPG-Pt) has been shown to exhibit several interesting catalytic properties, tied to its exceptionally high surface area; however, structural degradation may occur owing to thermal coarsening. To understand the effect of atmosphere chemistry on ther...

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Autores principales:	A. A. El-Zoka, B. Langelier, G. A. Botton, R. C. Newman
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2020
Materias:	Materials of engineering and construction. Mechanics of materials TA401-492
Acceso en línea:	https://doaj.org/article/96f0e2c510ed41e8a9f66c298a12d08c
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spelling	oai:doaj.org-article:96f0e2c510ed41e8a9f66c298a12d08c2021-12-02T11:51:10ZMorphological evolution of Pt-modified nanoporous gold after thermal coarsening in reductive and oxidative environments10.1038/s41529-020-00143-42397-2106https://doaj.org/article/96f0e2c510ed41e8a9f66c298a12d08c2020-12-01T00:00:00Zhttps://doi.org/10.1038/s41529-020-00143-4https://doaj.org/toc/2397-2106Abstract Nanoporous gold made by dealloying AgAuPt (NPG-Pt) has been shown to exhibit several interesting catalytic properties, tied to its exceptionally high surface area; however, structural degradation may occur owing to thermal coarsening. To understand the effect of atmosphere chemistry on thermal coarsening and degradation, and means of limiting it, this study focuses on the high-resolution characterization of NPG-Pt layers coarsened in reductive Ar-H2 atmosphere, and in oxidative air. Atom probe tomography (APT) analysis is performed on NPG-Pt, coarsened separately in either Ar-H2 or air, to characterize the atomic-scale chemical changes in the nanoligaments and to develop a mechanistic view of the inherent processes. A tendency of Ag to segregate to the surface during coarsening is found to lead to complete elimination of the nanoligament core-shell structures in both cases. Large Pt segregates form during coarsening in Ar-H2, but under the surface of the ligaments, having relatively little effect on the coarsening rate. The oxygen-induced segregation of Pt was observed to cause the inhibition of thermal coarsening after minor loss in surface area-to-volume ratio. Findings in this paper help in understanding further the thermal coarsening of heterogeneous nanomaterials made by dealloying, and the pertinent factors that come into play in different chemical environments.A. A. El-ZokaB. LangelierG. A. BottonR. C. NewmanNature PortfolioarticleMaterials of engineering and construction. Mechanics of materialsTA401-492ENnpj Materials Degradation, Vol 4, Iss 1, Pp 1-6 (2020)
institution	DOAJ
collection	DOAJ
language	EN
topic	Materials of engineering and construction. Mechanics of materials TA401-492
spellingShingle	Materials of engineering and construction. Mechanics of materials TA401-492 A. A. El-Zoka B. Langelier G. A. Botton R. C. Newman Morphological evolution of Pt-modified nanoporous gold after thermal coarsening in reductive and oxidative environments
description	Abstract Nanoporous gold made by dealloying AgAuPt (NPG-Pt) has been shown to exhibit several interesting catalytic properties, tied to its exceptionally high surface area; however, structural degradation may occur owing to thermal coarsening. To understand the effect of atmosphere chemistry on thermal coarsening and degradation, and means of limiting it, this study focuses on the high-resolution characterization of NPG-Pt layers coarsened in reductive Ar-H2 atmosphere, and in oxidative air. Atom probe tomography (APT) analysis is performed on NPG-Pt, coarsened separately in either Ar-H2 or air, to characterize the atomic-scale chemical changes in the nanoligaments and to develop a mechanistic view of the inherent processes. A tendency of Ag to segregate to the surface during coarsening is found to lead to complete elimination of the nanoligament core-shell structures in both cases. Large Pt segregates form during coarsening in Ar-H2, but under the surface of the ligaments, having relatively little effect on the coarsening rate. The oxygen-induced segregation of Pt was observed to cause the inhibition of thermal coarsening after minor loss in surface area-to-volume ratio. Findings in this paper help in understanding further the thermal coarsening of heterogeneous nanomaterials made by dealloying, and the pertinent factors that come into play in different chemical environments.
format	article
author	A. A. El-Zoka B. Langelier G. A. Botton R. C. Newman
author_facet	A. A. El-Zoka B. Langelier G. A. Botton R. C. Newman
author_sort	A. A. El-Zoka
title	Morphological evolution of Pt-modified nanoporous gold after thermal coarsening in reductive and oxidative environments
title_short	Morphological evolution of Pt-modified nanoporous gold after thermal coarsening in reductive and oxidative environments
title_full	Morphological evolution of Pt-modified nanoporous gold after thermal coarsening in reductive and oxidative environments
title_fullStr	Morphological evolution of Pt-modified nanoporous gold after thermal coarsening in reductive and oxidative environments
title_full_unstemmed	Morphological evolution of Pt-modified nanoporous gold after thermal coarsening in reductive and oxidative environments
title_sort	morphological evolution of pt-modified nanoporous gold after thermal coarsening in reductive and oxidative environments
publisher	Nature Portfolio
publishDate	2020
url	https://doaj.org/article/96f0e2c510ed41e8a9f66c298a12d08c
work_keys_str_mv	AT aaelzoka morphologicalevolutionofptmodifiednanoporousgoldafterthermalcoarseninginreductiveandoxidativeenvironments AT blangelier morphologicalevolutionofptmodifiednanoporousgoldafterthermalcoarseninginreductiveandoxidativeenvironments AT gabotton morphologicalevolutionofptmodifiednanoporousgoldafterthermalcoarseninginreductiveandoxidativeenvironments AT rcnewman morphologicalevolutionofptmodifiednanoporousgoldafterthermalcoarseninginreductiveandoxidativeenvironments
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Morphological evolution of Pt-modified nanoporous gold after thermal coarsening in reductive and oxidative environments

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