کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
190937 459710 2010 5 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Insight into the electroreduction of nitrate ions at a copper electrode, in neutral solution, after determination of their diffusion coefficient by electrochemical impedance spectroscopy
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی مهندسی شیمی (عمومی)
پیش نمایش صفحه اول مقاله
Insight into the electroreduction of nitrate ions at a copper electrode, in neutral solution, after determination of their diffusion coefficient by electrochemical impedance spectroscopy
چکیده انگلیسی

The electrochemical reduction of nitrate ions at a copper electrode in an unbuffered neutral aqueous solution is studied. Using a two compartment electrochemical cell, three stationary cathodic waves, noted P1, P2 and P3, were evidenced by cyclic voltammetry at −0.9, −1.2 and −1.3 V/SCE, respectively. By comparing the electrochemical response of nitrate and nitrite containing solutions, P1 was attributed to the reduction of nitrate to nitrite. In order to assign P2 and P3 features by determining the number of electrons involved at the corresponding potential, rotating disk electrode experiments at various rotation speeds, combined with linear sweep voltammetry, were performed. Current data analysis at a given potential was carried out using Koutecky–Levich treatment taking into account water reduction. Confident values of the diffusion coefficient D of nitrate ions were assessed by electrochemical impedance spectroscopy for nitrate concentrations of 10−3, 10−2 and 10−1 M. For a nitrate concentration of 10−2 M, D was found to be 1.31 × 10−5 cm2 s−1 allowing the number of electrons to be determined as 6 for P2 and 8 for P3, in accordance with nitrate reduction into hydroxylamine and ammonia, respectively. The formation of hydroxylamine was confirmed by the observation of its reoxidation at a Pt microelectrode present at the Cu electrode/nitrate solution interface.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Electrochimica Acta - Volume 55, Issue 24, 1 October 2010, Pages 7341–7345
نویسندگان
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