Synthesis, Characterization, and Study of NO2 Gas Sensing Behavior of CSA Doped PANi-Ta2O5 Nanocomposite

Polyaniline in its emeraldine salt form was obtained by chemical oxidative polymerization of aniline monomer. PANi thus obtained was mixed with tantalum pentoxide (Ta
₂
O
₅
) nano powder in 50 wt% to get PANi-Ta
₂
O
₅
nanocomposite. The nanocomposite was further mixed with Camphor Sulphonic Acid (CSA) with concentrations of 20wt%, 30wt% and 40wt% respectively for solid-state doping. All the samples were characterized by FESEM, TEM, XRD, FTIR and UV-Vis spectroscopy. Thin film sensor device was developed taking each of the samples as the sensing material to study the gas sensing properties towards NO
₂
gas at room temperature. The CSA doped nanocomposite possessed highly aggregated globular morphology that led to high surface area. Doping of CSA notably favored the gas sensing process. PANi-Ta
₂
O
₅
-CSA40wt% exhibited the best performance with sensor response above 80% towards 500 ppm NO
₂
, a faster response time of 55 seconds and a recovery time of 160 seconds. The device showed good repeatability and high selectivity to NO
₂
. The sensor response was studied under 38%, 57% and 65% relative humidity conditions respectively and it was found to remain stable under different humidity levels.