Fast gas sensors based on metal oxides which are stable at high temperatures

Recently, research into the characteristics of semiconductor metal oxides that are stable at high temperatures with a view to providing reproducible detection of oxygen and reducing gases has intensified. First of all, there is a discussion of the specifics relating to these materials, for example the reduction of the effects of grain-boundary barriers on the conduction mechanism, the reduction of the humidity cross-sensitivities and also on the various reaction mechanisms. Then, the technology for constructing gas sensors of this kind will be described. Examples that have already been implemented, for example, lambda, detection, O-2 measurements in the exhaust gases from incinerators, methane alarms, and air quality control, as well as certain trends in development, are discussed. (C) 1997 Elsevier Science S.A.