ELECTROCATALYST, METHODS FOR PREPARING IT, ELECTRODES PREPARED THEREFROM AND METHODS FOR USING THEM

摘要

The disclosed electrocatalyst material is useful in electrodes, especially in cathodes for the reduction of oxygen or peroxide to water or hydroxide. The electrocatalyst typically comprises 0.1 to 20 weight-%, total material weight, of supported crystalline elemental gold particles with exposed (100) faces, but smaller in size than 5 nanometers. These tiny monocrystals of gold are supported on carbon black or particulate conductive ceramic-like compounds having a B.E.T. surface area of at least 50 m<2>/g, and a substantial proportion of four-electron change reactions occur when oxygen is reduced. The electrodes are made by impregnating the support material with a reducible gold compound dissolved in a polar solvent, gently evaporating the solvent, chemically reducing the gold compound in situ at a moderate temperature with a flowing reducing gas then applying the supported gold to a porous backing material. Typical gold content levels at the electrode surface are < 2 mg/cm<2>.