Prototyping a Gas Sensors Using CeO2 as a Matrix or Dopant in Oxide Semiconductor Systems

In this chapter, two important aspects of using CeO2 in the field of gas sensors are presented. Firstly, for CO2 detection in the range of 0–5000 ppm, a binary semiconductor oxides CeO2-Y2O3 was used. Secondly, as a dopants, in oxide semiconductor systems, used to detect the NO2. In this case, CeO2 is used as a dopant in hybride composite, consisting of reduced graphene oxide/ZnO, in order to increase the sensibility in NO2 detection at low concentration in the range of 0–10 ppm. The structural and morphological characterization of sensitive materials by X-ray diffraction, SEM, adsorption desorption isotherms, thermal analysis and RAMAN spectroscopy are presented. Also, the sensing element of the sensor that detects the NO2 is achieved by depositing the nanocomposite material on the interdigital grid. The electronic conditioning signal from the sensing element is achieved by using a Wheatstone bridge together with an instrumentation operational amplifier.