Investigation of oxygen reduction on activated carbon electrodes in alkaline solution

Oxygen reduction has been studied on gas diffusion electrodes made from various kinds of activated carbon materials. The potentiodynamic method was used to study the electrochemical behavior of the reduction reaction, while nitrogen gas adsorption and powder Xray diffraction were used to determine the pore size distribution and the crystal structure of the carbon material, respectively. The relationship between the catalytic activity of activated carbon and the surface content of edge orientation was discussed. The specific catalytic activity of activated carbon is determined by the percentage of the edge orientation on the surface. The higher the content of the edge plane, the lower the oxygen reduction overpotential. The reduction overpotential is also related to the effective surface area, which determines the local current density. (C) 2007 Elsevier Ltd. All rights reserved.