Abstract
The electroreduction of nitrate and nitrite on iridium-deposited carbon fiber electrode in aqueous sodium perchlorate solutions of pH 7 was studied using cyclic voltammetric techniques. Results obtained on the modified electrode support a two-step nitrate reduction mechanism in which nitrate is first reduced to nitrite at Epeak = -800 mV (Ag/AgCl) during the negative scan and further reduced to ammonia at Epeak = -775 mV (Ag/AgCl) during the anodic scan. An oxidation peak for the unreduced nitrite was observed at -300 mV (Ag/AgCl). A Tafel slope of approximately 178 mV/dec and a pseudo-first-order rate constant of k° = 4.18×10-7 cm s-1 were determined for the cathodic reduction peak while Tafel slope of 18.9 mV/dec and k° = 2.62×10-23 cm s-1 were obtained for the anodic reduction peak. The Tafel slopes obtained also support the two-step mechanism. The results obtained strongly suggest a minimal effect of pH on nitrate reduction in the pH range of 2.0-13.0 in NaClO4 solution at the surface of iridium-coated carbon fiber electrode.
| Original language | English |
|---|---|
| Pages (from-to) | 4224-4228 |
| Number of pages | 5 |
| Journal | Journal of the Electrochemical Society |
| Volume | 147 |
| Issue number | 11 |
| DOIs | |
| State | Published - Nov 1 2000 |
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ASJC Scopus subject areas
- Electrochemistry
- Surfaces, Coatings and Films
- Surfaces and Interfaces
Cite this
Cyclic voltammetric studies of nitrate and nitrite ion reduction at the surface of iridium-modified carbon fiber electrode. / De, Dibyendu; Englehardt, James Douglas; Kalu, Egwu Eric.
In: Journal of the Electrochemical Society, Vol. 147, No. 11, 01.11.2000, p. 4224-4228.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Cyclic voltammetric studies of nitrate and nitrite ion reduction at the surface of iridium-modified carbon fiber electrode
AU - De, Dibyendu
AU - Englehardt, James Douglas
AU - Kalu, Egwu Eric
PY - 2000/11/1
Y1 - 2000/11/1
N2 - The electroreduction of nitrate and nitrite on iridium-deposited carbon fiber electrode in aqueous sodium perchlorate solutions of pH 7 was studied using cyclic voltammetric techniques. Results obtained on the modified electrode support a two-step nitrate reduction mechanism in which nitrate is first reduced to nitrite at Epeak = -800 mV (Ag/AgCl) during the negative scan and further reduced to ammonia at Epeak = -775 mV (Ag/AgCl) during the anodic scan. An oxidation peak for the unreduced nitrite was observed at -300 mV (Ag/AgCl). A Tafel slope of approximately 178 mV/dec and a pseudo-first-order rate constant of k° = 4.18×10-7 cm s-1 were determined for the cathodic reduction peak while Tafel slope of 18.9 mV/dec and k° = 2.62×10-23 cm s-1 were obtained for the anodic reduction peak. The Tafel slopes obtained also support the two-step mechanism. The results obtained strongly suggest a minimal effect of pH on nitrate reduction in the pH range of 2.0-13.0 in NaClO4 solution at the surface of iridium-coated carbon fiber electrode.
AB - The electroreduction of nitrate and nitrite on iridium-deposited carbon fiber electrode in aqueous sodium perchlorate solutions of pH 7 was studied using cyclic voltammetric techniques. Results obtained on the modified electrode support a two-step nitrate reduction mechanism in which nitrate is first reduced to nitrite at Epeak = -800 mV (Ag/AgCl) during the negative scan and further reduced to ammonia at Epeak = -775 mV (Ag/AgCl) during the anodic scan. An oxidation peak for the unreduced nitrite was observed at -300 mV (Ag/AgCl). A Tafel slope of approximately 178 mV/dec and a pseudo-first-order rate constant of k° = 4.18×10-7 cm s-1 were determined for the cathodic reduction peak while Tafel slope of 18.9 mV/dec and k° = 2.62×10-23 cm s-1 were obtained for the anodic reduction peak. The Tafel slopes obtained also support the two-step mechanism. The results obtained strongly suggest a minimal effect of pH on nitrate reduction in the pH range of 2.0-13.0 in NaClO4 solution at the surface of iridium-coated carbon fiber electrode.
UR - http://www.scopus.com/inward/record.url?scp=0034322132&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0034322132&partnerID=8YFLogxK
U2 - 10.1149/1.1394045
DO - 10.1149/1.1394045
M3 - Article
AN - SCOPUS:0034322132
VL - 147
SP - 4224
EP - 4228
JO - Journal of the Electrochemical Society
JF - Journal of the Electrochemical Society
SN - 0013-4651
IS - 11
ER -