Size-Controlled Synthesis of Gold Nanoparticles from Bulk Gold Substrates by Sonoelectrochemical Methods

摘要

Size-controlled gold nanoparticles,ranging from 2 to 15 nm in diameter,were first prepared from gold substrates in 0.1 N HC1 aqueous solutions without the addition of any stabilizers by Sonoelectrochemical methods.First,an Au substrate was cycled in a deoxygenated aqueous solution containing 0.1 N HC1 from -0.28 to + 1.22 V vs Ag/AgCl at 500 mV/s with 100 scans.The durations at the cathodic and anodic vertexes are 10 and 5 s,respectively.After this process,Au- and Cl-containing complexes were left in the solution.The Au working electrode was then immediately replaced by a Pt electrode,and cathodic overpotentials of 0.2,0.4,and 0.6 V from the open circuit potential (OCP) of ca.0.82 V vs Ag/AgCl were applied under sonification to synthesize Au nanoparticles.The prepared nanoparticles increase in size from 2 to 15 nm with the increase of the cathodic overpotential applied from 0.2 to 0.6 V.Furthermore,the ratio of Au nanoparticles to Au-containing nanocomplexes in solutions can be controlled by adjusting the Sonoelectrochemical reduction time.