Environment Controlled Dewetting of Rh-Pd Bilayers: A Route for Core-Shell Nanostructure Synthesis

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dc.authorid0000-0001-7933-7295
dc.authorid0000-0001-7933-7295
dc.authorid0000-0001-6138-8078
dc.authorid0000-0002-8973-6561
dc.authorid0000-0002-1933-8066
dc.authorid0000-0003-0455-1945
dc.contributor.authorAbrasonis, Gintautas
dc.contributor.authorWintz, Sebastian
dc.contributor.authorLiedke, Maciej O.
dc.contributor.authorAkgul, Funda Aksoy
dc.contributor.authorKrause, Matthias
dc.contributor.authorKuepper, Karsten
dc.contributor.authorGemming, Sibylle
dc.date.accessioned2019-08-01T13:38:39Z
dc.date.available2019-08-01T13:38:39Z
dc.date.issued2012
dc.departmentNiğde ÖHÜ
dc.description.abstractChemical environment plays a significant role on the size, shape, or surface composition of nanostructures. Here, the chemical environment effects are studied in the context of core-shell nanoparticle synthesis. The environment driven dynamics and kinetics of Rh/Pd bilayers is investigated by in situ ambient pressure X-ray photoelectron spectroscopy. Thin Rh (similar to 1.5 nm)/Pod ( similar to 1.5 nm) bilayers were grown on thermally oxidized Si substrates. The films were heated in CO or NO environments or heated in vacuum with a subsequent NO/CO cycling. This study demonstrates that not the initial stacking sequence but the chemical environment plays a crucial role in controlling the surface composition. Heating in CO results in a surface enrichment of Pd at similar to 200 degrees C and is followed by film dewetting at similar to 300 degrees C. Heating in NO results in progressive oxidation of Rh starting at similar to 150 degrees C, which stabilizes the film continuity up to >similar to 375 degrees C. The film rupture correlates with the thermal destabilization of the surface oxide. Heating in vacuum results in a significant increase in surface Pd concentration, and the following NO/CO cycling induces periodic surface composition changes. The quasi equilibrium states are similar to 50% and similar to 20% of Rh/(Rh + Pd). for NO and CO environments, respectively. Possible surface composition change and dewetting mechanisms are discussed on the basis of the interplay of thermodynamic (surface/oxide energy and surface wetting) and kinetic (surface oxidation and thermally induced and chemically enhanced diffusion) factors. The results open alternative ways to synthesize supported (core-shell) nanostructures with controlled morphology and surface composition.
dc.description.sponsorshipU.S. Department of Energy [DE-AC02-05CH11231]; EU [13857/2379]; Nanoskalige Funktionsschichten auf Kohlenstoffbasis; Deutsche Forschungsgemeinschaft [FA314/6-1]
dc.description.sponsorshipWe are thankful for the ALS staff for providing synchrotron research facilities. The Advanced Light Source is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. M.K. gives thanks for funding by the EU, "European regional development fund", Project ECEMP-D1 (13857/2379), "Nanoskalige Funktionsschichten auf Kohlenstoffbasis". This work was supported by Deutsche Forschungsgemeinschaft (Grant. No. FA314/6-1). We thank Mr. Stefan Bartkowski from the University of Osnabruck, Germany, and Dr. Helfried Reuther from Helmholtz-Zentrum Dresden-Rossendorf, Germany, for useful discussions.
dc.identifier.doi10.1021/jp302908x
dc.identifier.endpage14407
dc.identifier.issn1932-7447
dc.identifier.issue27
dc.identifier.scopus2-s2.0-84863821883
dc.identifier.scopusqualityQ1
dc.identifier.startpage14401
dc.identifier.urihttps://dx.doi.org/10.1021/jp302908x
dc.identifier.urihttps://hdl.handle.net/11480/4559
dc.identifier.volume116
dc.identifier.wosWOS:000306303800025
dc.identifier.wosqualityQ1
dc.indekslendigikaynakWeb of Science
dc.indekslendigikaynakScopus
dc.institutionauthor[0-Belirlenecek]
dc.language.isoen
dc.publisherAMER CHEMICAL SOC
dc.relation.ispartofJOURNAL OF PHYSICAL CHEMISTRY C
dc.relation.publicationcategoryMakale - Uluslararası Hakemli Dergi - Kurum Öğretim Elemanı
dc.rightsinfo:eu-repo/semantics/closedAccess
dc.titleEnvironment Controlled Dewetting of Rh-Pd Bilayers: A Route for Core-Shell Nanostructure Synthesis
dc.typeArticle

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