ELECTROCHEMICAL CONVERSION OF NITRATE TO AMMONIA IN WATER USING COBALT-DIM AS CATALYST

Co-DIM [DIM = methyl-1,4,8,11-tetraazacyclotetradeca-1,3-diene], a Co( cyclam) analog, is reported to catalyze the electrochemical reduction of nitrate to ammonia. The Co(II)/Co(I) reduction of this compound in aqueous sodium bromide solutions was nearly reversible on pyrolytic gr aphite electrodes. The complex was catalytically active for reduction of NO3- as well as its reduction intermediates NO2- and hydroxylamine. Ammonia was the sole product found after electrolysis of sodium nitra te in the presence of Co-DIM on a carbon felt cathode. (C) 1997 EIsevi er Science S.A.