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 (N 2 ) generation during the electrochemical oxidation of hydroxylamine (NH 2 OH), , 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 N 2 generated at the Au(poly) disk was assayed using the oxidation of hydrazine (N 2 H 4 ) in aqueous phosphate buffer (pH 7). This redox process yields N 2 as the only product, allowing a direct correlation to be established between the changes in the partial pressures of N 2 and the current flowing through the disk electrode. An analysis of the data collected revealed a strong dependence of both on pH and the applied potential. Although values of 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.