Abstract
ABSTRACTCatalysts of Co3O4 and Au/Co3O4 were prepared for sensing materials of CO sensor. Two types of CO sensors i.e. Solid electrolyte (SES) and semiconductor (SCS) were developed. For the sake of applicability, low working temperature, high sensitivity, good selectivity, fast response time and low cost are expected from the prepared sensors. Sensitivity of prepared catalysts towards CH4 and H2 also were tested in the experiment.In SES, yttria stabilized zirconia (YSZ) was used as the conductor of oxygen ions. Different oxides i.e. CoOx, SnO2, TiO2 and CuO were compared as catalysts in the anode to decrease partial pressure of oxygen. Co3O4 (S = 60 mV) showed higher CO sensitivity (S) than the other oxides. An addition of nanoparticles of Au to Co3O4 raised its CO sensitivity to S = 121 mV. The Au/Co3O4 could detect CO at T > 130 oC. The temperature was restricted by the oxygen ionic conductivity of YSZ disk.In SCS, CO could be detected by the conductivity of Co3O4 at 40 oC. The optimum working temperature of CO detection was about 80 oC (S = 3.8). An addition of nanoparticles of Au to Co3O4 did not improve the CO sensitivity. Both the response time of SES (YSZ) and SCS based on Co3O4 and Au/Co3O4 were short (< 1 min).