Reaction pathways in the electrochemical reduction of nitrate on tin

The reaction pathways that lead to the formation of intermediates and final products of the reduction of nitrate on tin at high overpotential were studied in this paper. Possible chemical or electrochemical reactions of the intermediates were investigated and discussed. A complex mechanistic scheme was proposed which describes the formation of all products apart from nitrogen, even though the latter is the main electrolysis product. Several simplified reaction schemes were investigated and each fitted to experimental data using a Bayesian approach. It was concluded that in order to describe the rate of nitrogen formation, another intermediate must be considered between nitrite and nitrogen. It is finally postulated that this intermediate is nitramide; however, further work in order to develop a method for determining the nitramide concentration is required to confirm that this is indeed the precursor of nitrogen.