A planar, impedancemetric NO2 sensor based on NiO nanoparticles sensing electrode

A planar, impedancemetric NO2 sensor with 8% yttria stabilized zirconia (YSZ) as electrolyte and NiO nanoparticles as sensing electrode and a Pt counter electrode was fabricated and tested. The nano-tructured NiO sensing electrode was fabricated by infiltrating aqueous solutions of nickel nitrate into porous layer in a bilayer yttria-stabilized zirconia (YSZ) pellet, followed by calcination at 800 degrees C for 3 h. The complex impedance of the device was measured in the frequency range of 0.1-100 kHz and in the temperature range of 500-600 degrees C, respectively. The resistance value (Z') of the device at low frequency varied with concentration of NO2 in sample gases. The response signal (vertical bar Z vertical bar(base) - vertical bar Z vertical bar(gas) at 0.1 Hz of the present device was found to vary almost linearly with the logarithm of NO2 concentration from 20 to 300 ppm at fixed oxygen concentrations at 500-600 degrees C. The present sensor has many advantages, such as, simple structure, easy preparation, fast response and high sensitivity. (C) 2012 Elsevier B.V. All rights reserved.