Amperometric nitrogen dioxide gas sensor: preparation of PAn/Au/SPE and sensing behaviour

Au/Nafion(R) and PAn (polyaniline)/Au/Nafion(R) were prepared by Takenaka-Torikai (T-T) chemical plating and the electrochemical polymerisation methods, respectively. Using Au/Nafion(R) as a working electrode, the sensitivity of NO2 gas sensor was obtained as 2.28 muA ppm(-1) when the gas flow rate was >300 ml min(-1). The potential window for limiting current was in the range of 0.3-0.1 V (versus Ag/AgCl/3 M NaCl aqueous solution) by using PAn/Au/Nafion(R) as a working electrode. The sensitivity of NO2 gas sensor decreased from 2.54 to 1.40 muA ppm(-1) when the potential for preparing PAn/Au/Nafion(R) increased from 0.8 to 1.0 V and gas flow rate was 300 mi min(-1) The diffusion resistance of NO2 through the gas film can be neglected for the gas how rate >300 mi min(-1) when Au/Nafion(R) and PAn/Au/Nafion(R) prepared at 0.8 and 0.9 V were used as working electrodes. (C) 2001 Elsevier Science B.V. All rights reserved.