Surface Modifications of a Carbon Anode Catalyst by Control of Functional Groups for Vitamin C Fuel Cells

Abstract

We report that electro-oxidation treatment of carbon paper generates specific functional groups, and controllable coating of metal oxide films on carbon surface alters capacitive behaviors. Electrochemical characteristics, I-V curves in fuel cells, and a structural analysis of XPS represent that the carboxyl group is the most effective functional group in an electro-oxidation of L-ascorbic acid. The appropriate film thickness of titania on electro-oxidized carbon electrode further increases fuel cell performance and electrostatic capacitance by facilitating electron transfer reaction. An excessive amount of titania on carbon reduces contribution of carboxyl groups to electro-oxidation of L-ascorbic acid resulting in decline of catalytic effects since they prohibit L-ascorbic acid molecules from access to the adsorption sites on the carbon surface.