Mechanistic aspects of nitrate ion reduction on silver electrode: estimation of O-NO2- bond dissociation energy using cyclic voltammetry

Voltammetric investigations of mechanistic aspects and estimation of thermo-chemical parameters of nitrate ion reduction at silver electrode, in alkaline medium are reported. The activation barrier determined from cyclic voltammetry fits a quadratic relation rather than the expected Butler-Volmer kinetics. Intrinsic barrier calculations show that the reduction of nitrate ion on silver follows a concerted mechanism, involving electron transfer initiated bond cleavage, followed by chemical reaction. The bond dissociation energy for the O-NO2- bond was estimated to be 48.40 kcal mol(-1), which matches well with the reported value of 47.5 kcal mol(-1), determined from photodissociation experiments.