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.
| Original language | English |
|---|---|
| Journal | ChemNanoMat |
| Volume | 3 |
| Issue | 7 |
| Pages (from-to) | 472-478 |
| Number of pages | 7 |
| ISSN | 2199-692X |
| DOIs | |
| Publication status | Published - 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