Steering the formation of supported Pt-Sn nanoalloys by reactive metal-oxide interaction
Neitzel A, Kovacs G, Lykhach Y, Tsud N, Kozlov SM, Skala T, Vorokhta M, Matolin V, Neyman KM, Libuda J (2016)
Publication Status: Published
Publication Type: Journal article
Publication year: 2016
Journal
Publisher: ROYAL SOC CHEMISTRY
Book Volume: 6
Pages Range: 85688-85697
Journal Issue: 89
DOI: 10.1039/c6ra18801j
Abstract
The formation of a supported Pt-Sn nanoalloy upon reactive metal-oxide interaction between Pt nanoparticles and a Sn-CeO2 substrate has been investigated by means of synchrotron radiation photoelectron spectroscopy and resonant photoemission spectroscopy in combination with density functional modeling. It was found that Pt deposition onto a Sn-CeO2 substrate triggers the reduction of Sn2+ cations yielding Pt-Sn nanoalloys at 300 K under ultra-high vacuum conditions. Three distinct stages of Pt-Sn nanoalloy formation were identified associated with the growth of (I) ultra-small monometallic Pt particles on a Sn-CeO2 substrate, (II) Pt-Sn nanoalloys on a Sn-CeO2 substrate, and (III) Pt-Sn nanoalloys on a stoichiometric CeO2 substrate. These findings suggest the existence of a critical size of monometallic Pt particles above which the formation of a Pt-Sn nanoalloy becomes favorable. In this respect, density functional modeling revealed a strong dependence of the formation energy of the PtxSn nanoalloy on the size of the Pt particle. Additionally, the thermodynamically favorable bulk and surface Pt/Sn stoichiometries were identified as two parameters that determine the composition of the supported Pt-Sn nanoalloys and limit the extraction of Sn2+ from the Sn-CeO2 substrate. Primarily, the formation of a bulk Pt3Sn alloy phase drives the growth of the Pt-Sn nanoalloy upon Pt deposition at 300 K. Upon annealing, Sn segregation on the surface of the Pt-Sn nanoalloy promotes further extraction of Sn2+ until the thermodynamically stable Pt/Sn concentration ratios of 3 for the bulk and approximately 1.6 for the surface are reached.
Authors with CRIS profile
Armin Neitzel
Lehrstuhl für Physikalische Chemie II
Yaroslava Lykhach
Lehrstuhl für Physikalische Chemie II
Jörg Libuda
Professur für Physikalische Chemie
Additional Organisation(s)
Involved external institutions
Univerzita Karlova v Praze / Charles University in Prague
Czech Republic (CZ)
Universitat de Barcelona (UB) / University of Barcelona
Spain (ES)
Czech Republic (CZ)
Universitat de Barcelona (UB) / University of Barcelona
Spain (ES)
How to cite
APA:
Neitzel, A., Kovacs, G., Lykhach, Y., Tsud, N., Kozlov, S.M., Skala, T.,... Libuda, J. (2016). Steering the formation of supported Pt-Sn nanoalloys by reactive metal-oxide interaction. RSC Advances, 6(89), 85688-85697. https://dx.doi.org/10.1039/c6ra18801j
MLA:
Neitzel, Armin, et al. "Steering the formation of supported Pt-Sn nanoalloys by reactive metal-oxide interaction." RSC Advances 6.89 (2016): 85688-85697.
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