Size and Crystallographic Orientation Controls of Gold Nanoparticles Electrodeposited on GC Electrodes

Abstract

Gold nanoparticles were electrodeposited onto glassy carbon-electrodes (nano-Au/GC) in the presence of two different additives, namely, cysteine and iodide ions. The electrochemical characterization of the electrodeposited nano-Au/GC electrodes was performed via the measurements of the reductive desorption patterns of a thiol (e.g., cysteine) self-assembled monolayer as well as the cyclic voltammetric response toward the oxygen reduction reaction in alkaline medium. The structural characterization of the electrodeposited Au nanoparticles was performed by the scanning electron microscope. The nano-Au/GC electrodes prepared in the presence of 100 μM cysteine were surprisingly found to be enriched in the Au(100) and Au(110) facets and are characterized by a relatively big particle size up to 300 nm as well as low particle density (number of particles per unit area). The Au nanoparticles prepared in the presence of 100 μMI−100 μMI− ions were found to be much enriched in the Au(111) facets and are characterized by a relatively narrow particle size distribution range (10-40 nm) as well as a high particle density. Analysis of the X-ray diffraction data revealed a significantly decreased ratio of Au(111) domains of the Au nanoparticles electrochemically deposited in the presence of cysteine. These preliminary results suggest a simple way to control the size as well as the preferential crystallographic orientations of gold nanoparticles. © 2004 The Electrochemical Society. All rights reserved.