An amperometric NO2 sensor based on nano-structured La0.75Sr0.25Cr0.5Mn0.5O3−δ prepared by impregnating method

An amperometric NO2 sensor using nano-structured perovskite-type oxide La0.75Sr0.25Cr0.5Mn0.5O3−δ (LSCM) as sensing electrode with Ce0.9Gd0.1O1.95 (CGO)electrolyte was fabricated. The LSCM particles were prepared in the porous CGO layer by impregnating method. The composition and microstructure of the sample were characterized by XRD and SEM, respectively. The properties of the sensor for monitoring NO2 were studied. The results showed that the LSCM particles in the range of 50–150 nm were homogeneously dispersed in the porous CGO layer. The response current was almost linear to NO2 concentration in the range between 20 and 300 ppm. With the temperatures increasing, the sensitivity increased and reached 111.36 nA ppm−1 at 500 °C. The sensor showed good response, recovery, reproducibility and stability. Although the response current was slightly affected by changing O2 concentrations in the range of 0–10 vol%, the influence was negligibly small.

► A novel amperometric NO2 sensor based on LSCM nano-particles as sensing electrode and CGO as electrolyte was fabricated. ► Successful preparation of nano-structured La0.75Sr0.25Cr0.5Mn0.5O3−δ has been done by simple impregnating method. ► The response current was almost linear to NO2 concentration in the range between 20 and 300 ppm. With the operating temperatures increasing, the sensitivity increases. ► The sensor showed good response, recovery, reproducibility and stability and the influence of O2 concentrations was negligibly small.