Oxygen reduction reaction on spontaneously and potentiodynamically formed Au/TiO2 composite surfaces

From aqueous solutions, gold was deposited on freshly polished titanium surface either by displacement reaction or by potentiodynamic polarization. Both of these procedures resulted in the formation of Au/TiO2 composite layer over the titanium surface, although with quite different Au content. The electrochemical behaviour of these composite layers was examined in 0.1 M NaOH solution, both oxygen free and oxygen saturated, using rotating disc technique. In the potential region of oxygen reduction reaction, the Au/TiO2 layer obtained by potentiodynamic polarization, displayed the voltammetric curve similar to that observed on (10 0) plane of Au monocrystal. The Koutecky-Levich analysis evidenced that 4e(-) route of oxygen reduction dominates on both type of composite layers. (c) 2007 Elsevier Ltd. All rights reserved.