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On the Electrooxidation and Amperometric Detection of NO Gas at the Pt/Nafion® Electrode
Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan 10617, ROC
* Author to whom correspondence should be addressed.
Received: 22 May 2003 / Accepted: 3 June 2003 / Published: 22 August 2003
Abstract: The electrochemical oxidation of nitric oxide (NO) gas at the Pt/Nafion® electrode has been studied at a concentration of 500 ppm. The electrooxidation of NO taking place over a wide potential range can be described by a transcendental equation, from which the half-wave potential of the reaction can be determined. For NO oxidation with appreciable overpotentials but negligible mass-transfer effects, the Tafel kinetics applies. The obtained charge transfer coefficient (a) and the exchange current density (io) are 0.77 and 14 mA/cm2, respectively. An amperometric NO gas sensor based on the Pt/Nafion® electrode has been fabricated and tested over the NO concentration range from 0 to 500 ppm. The Pt/Nafion® electrode was used as an anode at a fixed potential, preferably 1.15 V (vs. Ag/AgCl/sat. KCl), which assures current limitation by diffusion only. The sensitivity of the electrochemical sensor was found to be 1.86 mA/ppm/cm2. The potential interference by other gases, such as nitrogen dioxide (NO2) and carbon monoxide (CO), was also studied in the range 0-500 ppm. Both sensitivity for NO and selectivity of NO over NO2/CO show significant enhancement upon using a cyclic voltammetric (CV) activation, or cleaning procedure.
Keywords: Amperometric sensor; Interference gas; Nitric oxide (NO); Pt/Nafionâ electrode; Sensitivity
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MDPI and ACS Style
Ho, K.-C.; Hung, W.-T.; Yang, J.-C. On the Electrooxidation and Amperometric Detection of NO Gas at the Pt/Nafion® Electrode. Sensors 2003, 3, 290-303.
Ho K-C, Hung W-T, Yang J-C. On the Electrooxidation and Amperometric Detection of NO Gas at the Pt/Nafion® Electrode. Sensors. 2003; 3(8):290-303.
Ho, Kuo-Chuan; Hung, Wen-Tung; Yang, Jin-Cherng. 2003. "On the Electrooxidation and Amperometric Detection of NO Gas at the Pt/Nafion® Electrode." Sensors 3, no. 8: 290-303.