Preparation, characterization and gas sensitivity studies of MWCNTs-doped PANI nanocomposites

0.02wt% multi-wall carbon nanotubes (MWCNTs) doped polyaniline (PANI) nanopowders were prepared by chemical polymerization of protonic acid method in 0°C water bath. The PANI and 0.05wt% MWCNTs-doped PANI nanopowders were prepared by the same way. The morphology and structure of PANI, MWCNTs-doped PANI nanopowders were analyzed by XRD, FT-IR and SEM. Gas sensors were fabricated based on PANI, 0.02wt% MWCNTs-doped PANI and 0.05wt% MWCNTs-doped PANI. The response sensitivity of gas sensors to NH3 was measured in NH3 concentration range of (0.1-1.5)×10-4. The response curves of three gas sensors were basically linearity. The response sensitivity of the gas sensor based on 0.02wt% MWCNTs-doped PANI was the highest, the responses were 27.65 and 1.94 for 1.5×10-4 NH3 and 1.0×10-5 NH3, respectively. The stability of the gas sensor based on 0.02wt% MWCNTs-doped PANI was tested, and the sensor showed good stability in three months. The sensing mechanism of MWCNTs-doped PANI gas sensor was analyzed.