Influence of process parameters on the sensitivity of an amperometeric NO2 sensor with La0.75Sr0.25Cr0.5Mn0.5O3−δ sensing electrode prepared by the impregnation method

Perovskite-type oxide La0.75Sr0.25Cr0.5Mn0.5O3−δ (LSCM) as sensing electrode for detection of NO2 was fabricated by impregnating the porous Ce0.9Gd0.1O1.95 (CGO) backbone with LSCM precursor solution. The sensing performances of the amperometric type sensor prepared under different conditions were investigated. The results indicated that the sensitivity of the sensor was strongly dependent on the LSCM loading level, CGO porous layer thickness, polarization potential and LSCM fabricating temperature. The influences of the LSCM loading and porous backbone thickness on the sensing performance of the sensor suggested that the porous structure of CGO backbone was not only appropriate for preparing nano-structure LSCM sensing electrode by impregnation, but also helpful for the mass transfer of NO2 to the triple phase boundary. When the applied potential moved negatively, the response current and sensitivity increased. Increasing the calcining temperature could improve the adhesion of LSCM to CGO backbone which was in favor of better sensing performance while increasing the LSCM particle size which resulted in the dropping of response current and sensitivity.