Electrochemical insight into the brust–schiffrin synthesis of Au nanoparticles

DOI: 10.1021/jacs.5b07825
PMID: 26559785

Authors: Akihiro Uehara (University of Manchester) , Samuel Booth (University of Manchester) , Sin-Yuen Chang (University of Manchester) , Sven L. M. Schroeder (The University of Manchester) , Takahito Imai (Ryukoku University) , Teruo Hashimoto (University of Manchester) , J. Frederick W. Mosselmans (Diamond Light Source) , Robert A. W. Dryfe (University of Manchester)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of The American Chemical Society , VOL 137 (48) , PAGES 15135–15144

State: Published (Approved)
Published: November 2015
Diamond Proposal Number(s): 11293 , 8861

Abstract: The mechanism of the Brust-Schiffrin gold nanoparticle synthesis has been investigated through the use of ion transfer voltammetry at the water|1,2-dichloroethane (DCE) solution interface, combined with X-ray absorption fine structure (XAFS) of the reaction between [AuCl4]- and thiol (RSH) in homogeneous toluene (TL) solution. Ion transfer calculations indi- cate the formation of [AuCl2]- at RSH:Au ratios from 0.2 – 2 with a time-dependent variation observed over several days. At RSH:Au ratios above 2 and after time periods greater than 24 hours, the formation of Au(I)SR is also observed. The relative concentrations of reaction products observed at the liquid/liquid interface are in excellent agreement with those observed by XAFS for the corresponding reaction in a single homogeneous phase. BH4- ion transfer reactions between water and DCE indicate that the reduction of [AuCl4]- and/or [AuCl2]- to Au nanoparticles by BH4- proceeds in the bulk organic phase. On the other hand, BH4- was unable to reduce the insoluble [Au(I)SR]n species to Au nanoparticles. The number and size of the nanoparticles formed was dependent on the concentration ratio of RSH:Au, as well as the experimental duration because of the competing formation of the [Au(I)SR]n precipitate. Higher concentrations of nanoparticles, with diameters of 1.0 – 1.5 nm, were formed at RSH:Au ratios from 1 to 2.

Journal Keywords: Thiols; Ions; Redox reactions; Water; Gold

Subject Areas: Chemistry, Materials


Instruments: B18-Core EXAFS , I18-Microfocus Spectroscopy

Added On: 12/11/2015 08:16

Documents:
jacs.5b07825.pdf

Discipline Tags:

Physical Chemistry Chemistry Nanoscience/Nanotechnology

Technical Tags:

Spectroscopy X-ray Absorption Spectroscopy (XAS) X-ray Absorption Near Edge Structure (XANES)