In Situ PDF Study of the Nucleation and Growth of Intermetallic PtPb Nanocrystals1. Issue 7 (29th May 2017)

• Record Type: Journal Article
• Authors: Saha, Dipankar; Bøjesen, Espen D.; Mamakhel, Aref Hasen; Bremholm, Martin; Iversen, Bo B.
• Is Part Of: ChemNanoMat. Volume 3:Issue 7(2017)
• Page Start: 472
• Page End: 478
• Publication Date: 2017-05-29
• Subjects: continuous flow synthesis -- intermetallic -- nanoparticles -- pair distribution function -- supercritical ethanol; Nanochemistry -- Periodicals; Nanostructured materials -- Periodicals; Nanochemistry; Nanostructured materials; Periodicals; 541.2
• DOI: 10.1002/cnma.201700069
• Languages: English
• ISSNs: 2199-692X

Abstract

Abstract: 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. Abstract : In situ total scattering studies provide a deeper understanding of the nucleation mechanism kinetics of Pt nanoparticle formation, and allow structural modelling of the precursor structure. The similar reaction kinetics of Pt(acac)2 and Pb(acac)2 precursors lead to development of a facile continuous flow supercritical ethanol process for obtaining phase pure hexagonal PtPb nanocrystals.