Meniscus behavior and oxygen reduction in tapered pore gas diffusion electrodes

Abstract

The electrochemical reduction of oxygen in 0.88 M KOH at 25°C was studied using two silver plated copper electrodes that contained uniform, parallel, tapered pores. Photolithography, etching, and plating techniques were used to fabricate these electrodes. Exchange current densities of 2 × 10-5 A cm-2 and 2 × 10-6 A cm-2 were measured using an initial slope method. Diffusion limiting currents increased with differential pressure across the gas-electrolyte interface which suggests smaller contact angles at higher pressures. A wedge meniscus model that treats activation, ohmic, and concentration overpotential was applied to fit the polarization curves. © 1988.