Detection of toxic gases using a composite of single-walled carbon nanotubes with polyaniline

We reported on the response behaviours of a composite sensor of SWNTs with polyaniline to detect noxious gases at room temperature. The SWNT-polyaniline composite synthesised was found to be high-quality with good uniformity. A combination of photolithography and a lift-off process was utilised to fabricate 100-nm thick Pd electrodes on drop-cast SWNT-polyaniline composite. The composite-based sensor showed high sensitivities to NH₃ concentration of 35 ppm and CO concentration of 50 ppm at room temperature. The observed sensitivity was 4% and -5.5% for the respective gas species in air. These results indicate that SWNT-polyaniline composite sensors employing Pd electrodes can be a good candidate for a noxious gas sensor that is able to simultaneously detect multiple gases in different modes down to minimal concentrations at room temperature.