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

Abstract

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.