Synthesis of Polyoxometalate-Protected Gold Nanoparticles by a Ligand-Exchange Method: Application to the Electrocatalytic Reduction of Bromate

✍ Scribed by Andrzej Z. Ernst; Laisheng Sun; Kamila Wiaderek; Aneta Kolary; S. Zoladek; Pawel J. Kulesza; James A. Cox

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 273 KB
• Volume: 19
• Category: Article
• ISSN: 1040-0397
• DOI: 10.1002/elan.200703925

✦ Synopsis

Abstract

Gold nanoparticles (AuNPs) protected by an alkanethiol in nonaqueous solvent are converted to AuNPs with a surrounding layer of a polyoxometalate, AuNP‐POM, by ligand exchange and liquid–liquid extraction into aqueous solution without changing the size of the metal core. With glassy carbon electrodes modified with PMo~12~‐AuNP (PMo~12~=H~3~PMo~12~O~40~), the reduction of bromate was mediated by the first redox process of the Mo^VI^ centers; the reduction occurred at a lower overpotential and yielded a higher cathodic current than that observed with PMo~12~ alone as the mediator. This synergistic electrocatalysis, which approached a linear diffusion‐controlled process, was used to demonstrate the feasibility of the determination of bromate. A detection limit of 3 μM (k=3 criterion) was achieved by pulse voltammetry.