In Situ PDF Study of the Nucleation and Growth of Intermetallic PtPb Nanocrystals

Publication: Research - peer-reviewJournal article

DOI

The mechanism of Pt and PtPb nanocrystal formation under supercritical ethanol conditions has been investigated by means of in situ X-ray total scattering and pair distribution function (PDF) analysis. The metal complex structures of two different platinum precursor solutions, chloroplatinic acid and Pt(acac)(2) (acac=acetylacetonate) provide atomic-scale detail about the nucleation mechanisms after initiation of the reaction with Pb(acac)(2) by heating. The stronger Pt-O chemical bonding in the Pt(acac)(2) precursor complex compared with the Pt-Cl bonding in the chloroplatinic acid precursor complex leads to a much slower reduction of the Pt center, and this allows more optimal co-reduction conditions providing a pathway for formation of phase-pure intermetallic PtPb product. The matching chemistry of the Pt(acac)(2) and Pb(acac)(2) precursors allow development of a facile continuous flow supercritical ethanol process for obtaining phase-pure hexagonal PtPb nanocrystals. The study thus highlights the importance of in situ studies in revealing atomic-scale information about nucleation mechanisms, which can be used in design of specific synthesis pathways, and the new continuous-flow process to obtain PtPb nanocrystals holds potential for large-scale production.

Original languageEnglish
JournalChemNanoMat
Volume3
Issue number7
Pages (from-to)472-478
Number of pages7
ISSN2199-692X
DOIs
StatePublished - Jul 2017

    Keywords

  • continuous flow synthesis, intermetallic, nanoparticles, pair distribution function, supercritical ethanol, X-RAY-SCATTERING, PAIR DISTRIBUTION-FUNCTIONS, METAL-OXIDE NANOPARTICLES, CONTINUOUS-FLOW SYNTHESIS, ELECTROCATALYTIC ACTIVITY, SUPERCRITICAL FLUIDS, HYDROTHERMAL SYNTHESIS, FUEL-CELLS, POWDER DIFFRACTION, SYNCHROTRON-RADIATION

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