NOx sensors based on YCoO3 perovskite

YCoO3 perovskite powder was prepared by gel combustion method, which was extended to the preparation also of non-stoichiometric materials and samples containing Pt or Pd. This preparation route allows for increasing the surface area and hence the surface reactivity. The powders were characterized in terms of composition and microstructure using XRD and SEM-EDX; moreover, the powder surface properties were investigated by studying their adsorptive features towards oxygen and their redox behavior by means of TPD and TPR, respectively. Some sensors hosting sensing films obtained from the prepared powders were realized by a screen-printing technique. The response to NOx and to some interfering gases (CH4, CO) were evaluated. Promising results were obtained at temperatures around 180 °C, where the sensitivities towards NOx result satisfactory high (2 %/ppm) and the responses result very fast, also in the recovery phase.