On the use of ammonia electrolysis for hydrogen production

An ammonia alkaline electrolytic cell for the production of hydrogen is presented. Challenges involved in using ammonia electro-oxidation for sustainable, low-cost, high-purity hydrogen production are identified and solutions are proposed. Electrodeposition was selected as a technique of preparing low-loading ammonia electrocatalysts. The efficiency of the electrolytic cell was improved by using bimetallic electrodeposited catalysts (at both electrodes) containing Pt and a low concentration of secondary metals (Ru, Ir). Pt-Ir deposits showed the highest activity toward ammonia oxidation. An experimental procedure is shown which minimizes the reversible deactivation of the electrode. Significant cur-rent densities were obtained (above 100 mA cm(-2)) during electrolysis testing at relatively low metal loading, low cell voltages, and high cell efficiencies. These results point to ammonia electrolysis as a promising candidate for an alternative process for low-cost, low-temperature, high-purity hydrogen production. (c) 2004 Elsevier B.V. All rights reserved.