Mechanistic aspects of nitrate ion reduction on silverelectrode: estimation of O–NO2− bond dissociation energy using cyclic voltammetry

Abstract

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.