Influence of Water Vapor on a NASICON-based NO₂ Sensor Operative at Room Temperature

Abstract

Two types of NASICON-based NO₂ sensors were fabricated by combining NASICON disk with two kinds of sensing electrode materials, such as (ITO, NaNO₂) and (ITO, NaNO₂-Li₂CO₃), and their NO₂ sensing properties investigated under the wet conditions at 30 ºC. The NO₂ sensitivity of the (ITO, NaNO₂)-attached device became large with increasing relative humidity below 30 %RH, whereas the NO₂ sensitivity decreased in the range of 30 - 50 %RH. In addition, the EMF at a fixed NO₂ concentration (1.9 ppm) shifted it upward with the change of relative humidity. On the other hand, the (ITO, NaNO₂-Li₂CO₃)-attached device did not almost interfered with water vapor.