THE ANODIC OXIDATION OF AMMONIA AT PLATINUM BLACK ELECTRODES IN AQUEOUS KOH ELECTROLYTE

Electrochemical kinetic studies are reported on the anodic oxidation of ammonia in aqueous potassium hydroxide solutions at platinum black electrodes. A kinetic scheme of consecutive reactions is proposed; Tafel slopes are deduced for various rate-determining mechanisms and compared with the experimental behavior. The reaction pathway is correlated with that involved in the analogous catalyzed ammonia vapor decomposition. The exchange currents obtained, compared with those for hydrogen oxidation, render the system unfavorable for fuel cell applications.