New insight into the electroreduction of nitrate ions at a copper electrode, in neutral solution
Résumé
The electroreduction of nitrate ions was investigated at a copper electrode in an unbuffered neutral aqueous solution. In the presence of nitrates, cyclic voltammetry revealed three cathodic waves. Rotating disk electrode measurements and the effect of potential scan rate were combined to further explore the reaction mechanism. Taking into account water reduction and using Koutecky-Levich analyses of the data obtained with linear sweep voltammetry at various electrode rotation rates, the number of electrons involved in the global reaction was found to be 2, 7 and 8, in accordance with nitrate reduction into nitrite, hydrazine and ammonia, respectively. Finally, we suggest that nitrogen oxides due to ammonia oxidation at the Pt counter electrode adsorb on copper electrode and block the nitrate reduction.
Domaines
Chimie
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