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Supercritical flow synthesis of Pt1-xRux nanoparticles: comparative phase diagram study of nanostructure versus bulk

hal.structure.identifierDepartment of Chemistry and iNANO
dc.contributor.authorBONDESGAARD, Martin
hal.structure.identifierDepartment of Chemistry and iNANO
dc.contributor.authorMAMAKHEL, Aref
hal.structure.identifierDepartment of Chemistry and iNANO
dc.contributor.authorBECKER, Jacob
hal.structure.identifierDepartment of Chemistry and iNANO
hal.structure.identifierFaculty of Pure and Applied Sciences, TIMS and CiRfSE
dc.contributor.authorKASAI, Hidetaka
hal.structure.identifierInstitut de Chimie de la Matière Condensée de Bordeaux [ICMCB]
dc.contributor.authorPHILIPPOT, Gilles
hal.structure.identifierDepartment of Chemistry and iNANO
dc.contributor.authorBREMHOLM, Martin
hal.structure.identifierDepartment of Chemistry and iNANO
dc.contributor.authorIVERSEN, Bo B.
dc.date.issued2017
dc.identifier.issn0897-4756
dc.description.abstractEnThe thermodynamic stability of nanocrystals is different from that of bulk systems, and nanoscale phase diagrams are to a large degree unknown. Here we present a systematic investigation of the Pt1–xRux phase diagram through supercritical flow synthesis of Pt1–xRux nanoparticles across the entire compositional range. The synthesis was done in stoichiometric steps of 0.1 using an ethanol–toluene mixture as solvent at 450 °C and 200 bar. The products were characterized by high-resolution synchrotron powder X-ray diffraction, transmission electron microscopy, and elemental mapping of individual particles using energy-dispersive X-ray spectroscopy. The diffraction data revealed a single-phase face-centered cubic (fcc) alloy for x ≤ 0.2, while an additional hexagonal close-packed (hcp) phase emerges as x approaches 1. This behavior deviates significantly from the bulk phase diagram, where a biphasic region is only observed for 0.62 < x < 0.8. Thus, compositional design of Pt–Ru alloys is more flexible on the nanoscale, opening up significant possibilities for catalyst optimization. Rietveld refinements and microstructural line profile analysis show that the fcc unit cell dimensions follow Vegard’s law within a good approximation. On the other hand, crystallite size, microstrain, phase content, and hcp c/a ratio depend nonlinearly on x but show some correlation to the bulk phase diagram. Elemental mapping shows the nanoparticles to be homogeneous, but in some cases, fcc–hcp phase boundaries and modulations in the elemental distribution were observed. All samples below x < 0.3 exhibit a spherical morphology. At higher ruthenium content, x ≥ 0.3, another morphology emerges with elongated particles together with the dominating spherical mophology. The TEM average particle sizes range from 5.0(8) to 10.4(7) nm.
dc.language.isoen
dc.publisherAmerican Chemical Society
dc.title.enSupercritical flow synthesis of Pt1-xRux nanoparticles: comparative phase diagram study of nanostructure versus bulk
dc.typeArticle de revue
dc.identifier.doi10.1021/acs.chemmater.7b00586
dc.subject.halChimie/Matériaux
bordeaux.journalChemistry of Materials
bordeaux.page3265-3273
bordeaux.volume29
bordeaux.issue7
bordeaux.peerReviewedoui
hal.identifierhal-01537451
hal.version1
hal.popularnon
hal.audienceInternationale
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-01537451v1
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