ELECTROCHEMICAL-BEHAVIOR OF SODIUM-AZIDE AT PT AND AU ELECTRODES IN SODIUM-SULFATE ELECTROLYTE

The electro-oxidation and -reduction of sodium azide at porous painted platinum and gold electrodes was studied using the multipurpose electrochemical mass spectrometry (MPEMS) which was operated in the differential electrochemical mass spectrometry (DEMS) mode. The platinum electrode was found to be active for electro-oxidation as well as for electroreduction. Above 0.3 V vs. Hg/Hg2SO4, azide is oxidized to give N-2, NO, NO2, and N2O. Reduction of azide takes place below -0.9 V forming N-2, N2H4, and possibly NH3. In contrast to platinum, gold showed only activity for the electro-oxidation of azide leading to the formation of N-2, NO, NO2, and N2O above 0.5 V. Evidence for a reaction without evolution of volatile products was also found taking place above 0.1 V. A reaction mechanism is discussed emphasizing the role of adsorbed hydrogen and oxygen.