Adsorption characteristics of Fe(CN)36-/4 on Au colloids as monolayer films on cysteamine-modified gold electrode

Self-assembled monolayers (SAMs) of chemisorbed cysteamine on gold electrode surfaces have been used as base interfaces for the deposition of the An colloid. Different Au colloids, ranging in particles of diameter 2.6, 16, 42 and 51 nm, can be deposited on self-assembled cysteamine monolayers on a gold electrode. Fe(CN)(6)(4-) adsorbed on Au colloid surfaces yields a pair of symmetric adsorption peaks with half-peak width (W-1/2) of 90.2 mV and peak-to-peak separation (Delta E-p) of 3 mV in 1.0 M KNO3 solution containing 1.00 x 10(-3) M K3Fe(CN)(6). The dependence of peak current on scan rate (nu) is linear. Delta E-p of the adsorption wave increases while the Au colloid size decreases. The apparent specific capacitances of a bare gold electrode, the cysteamine-modified electrode and the Au colloid modified electrode measured by cyclic voltammetry at 500 mV are 57.8, 32.0 and 81.1 mu F cm(-2), respectively. (C) 1999 Elsevier Science S.A. All rights reserved.