Hydroxylamine Oxidation on Polycrystalline Gold Electrodes in Aqueous Electrolytes: Quantitative On‐Line Mass Spectrometry under Forced Convection

Abstract

Herein, a method is presented that allows quantitative determination of faradaic efficiencies for dinitrogen (N2) generation during the electrochemical oxidation of hydroxylamine (NH2OH), fN2NH2OH , on a polycrystalline gold Au(poly) disk electrode in aqueous electrolytes over a wide pH range. This tactic involves the use of an impinging jet electrolyte configuration incorporating a gas porous ring connected in turn to a mass spectrometer. The actual amount of N2 generated at the Au(poly) disk was assayed using the oxidation of hydrazine (N2H4) in aqueous phosphate buffer (pH 7). This redox process yields N2 as the only product, allowing a direct correlation to be established between the changes in the partial pressures of N2 and the current flowing through the disk electrode. An analysis of the data collected revealed a strong dependence of fN2NH2OH both on pH and the applied potential. Although values of fN2NH2OH as high as 20 to 30 % were found in acid and neutral media over a narrow potential region, those in alkaline solution were far smaller in the entire potential range examined.

Unraveling the Mechanism of Ammonia Electrooxidation by Coupled Differential Electrochemical Mass Spectrometry and Surface-Enhanced Infrared Absorption Spectroscopic Studies

“…The knowledge of their electrocatalytic reactions could advance the understanding of the AOR mechanism. The electrocatalytic reduction and oxidation mechanism of these N-containing species have also been studied. ,− …”