Niobium pentoxide as a lean-range oxygen sensor

Niobium pentoxide (Nb2O5) has been investigated as a lean-burn oxygen senso r in the 400-800 degrees C temperature range. It shows excellent sensitivit y and good reversibility upon exposure to increasing and decreasing oxygen partial pressures. In the 10 ppm to 100% oxygen partial pressure range, the response of Nb2O5 sensor is as fast as the YSZ sensor. There is a change i n the resistance when Nb2O5 is exposed to CO, CH4 and CO2. However, this ch ange in the resistance is mainly due to a change in the ambient oxygen part ial pressure, though there might be a small amount of cross-sensitivity eff ect. This cross-sensitivity effect has been isolated for CO2. Humidity does n't show much cross-sensitivity effect on the Nb2O5 sensor. (C) 1999 Elsevi er Science S.A. All rights reserved.