Polyaniline-MWCNT Based CO₂ Gas Sensor Operable at Room Temperature

In this research work, a polyaniline-multiwalled carbon nanotube (MWCNT)-based gas sensor is fabricated and tested for CO₂ gas at room temperature. Polyaniline-MWCNT (PCT) composites were synthesized through a chemical oxidation process using FeCl₃ as an oxidant. The polymerization process was conducted at room temperature. The PCT composites were characterized using XRD, FTIR, UV spectroscopy, scanning electron microscopy (SEM), and impedance spectroscopy. The PCT 15% shows highest sensitivity at room temperature. XRD and FTIR spectroscopy confirm the formation of a PCT composite. SEM image confirmed the change in morphological structure for PCT 15% composite than pure polyaniline. Through impedance spectroscopy, it was found that all the composites show conductive properties as their phase angle is less than 90°. The response and recovery time of PCT (5%, 10%, 15%, and 20%) was found to be (148 s, 121 s), (125 s, 141 s), (110 s, 261 s), and (121 s, 63 s).