Ambient temperature operable Bi-Co ferrite NO2 sensors with high sensitivity and selectivity

Abstract The sol-gel chemical synthesis, reaction mechanism, structural, morphological and elemental scanning measurements of bismuth (Bi3+)-doped spinel cobalt ferrite (Bi-Co ferrite) film sensors are explored. The gas sensor studies of Bi-Co ferrite sensors performed on methanol, ethanol, hydrogen sulphide, ammonia and nitrogen dioxide (NO2) gases at 230 °C as operating temperature where, Bi-Co ferrite sensors are extremely selective towards NO2 gas compared with other gases which is attributed to its high electron donating power. Furthermore, a small 31/29 s response/recovery time value and low detection limit of 25 ppm are evidently been proved its practical application potential. These results helped us to understand the sensing mechanism in Bi-Co ferrite sensors and provided a hint for tuning the conductivity/resistance of metal oxide semiconductor-based gas sensors.