Mesoporous carbon functionalized with ferrocenecarboxylic acid and its electrocatalytic properties

The characterization of ordered mesoporous carbon (OMC) material functionalized with ferrocenecarboxylic acid (Fc) is reported. The results show that, after anchoring ferrocene on the mesoporous, ordered mesostructure of the material (OMC-Fc) remains intact. The electrochemical characterization of OMC-Fc shows that Fc is electrochemically accessible. In aqueous buffer solution (pH 7.3), the OMC-Fc modified electrode shows high electrocatalytic activity towards ascorbic acid (AA) oxidation with a decrease of overpotential and a drastic enhancement of the anodic currents compared to the bare glassy carbon (GC) electrode. It has been found that the electrocatalytic properties are influenced by the nature of the binder. With polyvinyl alcohol (PVA) as a binder, the decrease in the overvoltage is 200 mV whereas with Nafion, the decrease of overpotential is about 400 mV. Thus, compared to PVA, Nafion offers the best conditions of elect rocatalytic oxidation of AA and further studies were done in these conditions. The reaction is limited by the mass transport process and Fc immobilized on OMC acts as a mediator. The catalytic current of AA versus its concentration shows a good linearity in the range of 5 x 10(-5)-35 x 10(-5) M, With a correlation coefficient of 0.997 and a detection limit of 9 x 10(-6) M. (C) 2007 Elsevier Inc. All rights reserved.