AmericanChemicalSociety.com

Research Report

Research has focused on gold electrodes decorated with platinum. A detailed study of the structure of the deposits was made using atomic force microscopy and scanning tunneling microscopy. It was shown that the deposits are very nonuniform. However, they are effective catalysts for the electroreduction of oxygen. The fabrication of the decorated electrodes and their properties was described in a paper presented to a meeting of the International Society of Electrochemistry on Electrocatalysis [1]. The mechanism of oxygen reduction was studied using a rotating ring disc electrode which showed that it took place in perchloric acid in a one step reaction involving four electrons:

O₂ + 4 H⁺ + 4 e^-  ¾® 2 H₂O                                              (1)

Recent work has involved a study of the mechanism of oxygen reduction at decorated gold electrodes in room temperature ionic liquids (RTILs). One such liquid is 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF₄). This is an aprotic system with a dielectric constant of 15 and a conductivity of 1,4 W^-1 m^-1. A study of its double layer properties showed that the diffuse layer is very different in RTILs compared to more dilute electrolytes [2]. The kinetics of oxygen reduction is being studied as a function of the nature and concentration of simple acids added to EMImBF₄ such as HCl and HNO₃. RTILs are of great interest for incorporation into supercapacitors and fuel cells.

1. D. Misicak, T. Ruthenburg, and W. R. Fawcett, Copper Deposition and its

Replacement by Platinum on a Gold Electrode, Electrochim. Acta, in press.

2. W. R. Fawcett and P. J. Ryan, The Diffuse Double Layer in Ionic Liquids,

Coll. Czech. Chem. Comm., 74 (2009) 1665-1674.