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Hydroxylamine Oxidation on Polycrystalline Gold Electrodes in Aqueous Electrolytes: Quantitative On‐Line Mass Spectrometry under Forced Convection
Author(s) -
Pozniak Boguslaw,
Treufeld Imre,
Scherson Daniel
Publication year - 2019
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201900367
Subject(s) - hydroxylamine , chemistry , aqueous solution , electrolyte , electrochemistry , inorganic chemistry , rotating disk electrode , analytical chemistry (journal) , electrode , redox , mass spectrometry , hydrazine (antidepressant) , cyclic voltammetry , organic chemistry , chromatography
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), f N 2N H 2 O H , 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 f N 2N H 2 O H both on pH and the applied potential. Although values of f N 2N H 2 O Has 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.