Nanoporous amorphous manganese oxide as electrocatalyst for oxygen reduction in alkaline solutions

A nanoporous amorphous manganese oxide is investigated as electrocatalyst for the oxygen reduction reaction in alkaline solutions. Cyclic voltammetry of catalytic electrodes based on the amorphous manganese oxide in oxygen-saturated electrolytes indicates that the amorphous manganese oxide catalyzes a two-electron reduction of molecular oxygen to HO2-. An oxygen reduction current density of more than 100 mA/cm(2) is attained with an oxygen back-feed gas diffusion electrode with a low-catalyst loading of ca. 0.85 mg/cm(2). The significant catalytic activity might be due to high concentration of lattice defects and active sites of the amorphous material, which would have potential applications in metal-air batteries and low-power fuel cells. (C) 2003 Elsevier Science B.V. All rights reserved.