Sensing analysis of polyaniline – stannous chloride pentahydrate composite of CO2 gas sensors

Abstract

ABSTRACT In this experimental work, the composite of polyaniline-stannous chloride pentahydrate (PSCL) was synthesized at room temperature through polymerization using FeCl3 as an oxidant. The sensing was carried out at room temperature for a 150 ppm concentration of CO2 gas. The PSCL composite was coated on a glass substrate. The PSCL composite was characterized by XRD, FTIR, and Impedance spectroscopy analysis. XRD and FTIR confirm the formation of SnO2 particles in composites. The ideal capacitor will have phase angle at −90° which is shown by PSCL (10% and 20%) composites which indicate that they have lower ionic permeability and show there insulating properties. Whereas composites PSCL (5% and 15%) at low frequency show high ionic permeability, as they have phase angle near to −45° which makes them poor insulators. The response and recovery times of composites are [130 s, 31 s], [142 s, 556 s], [134 s, 98 s], and [113 s, 90 s] for PSCL 5%, 10%, 15%, and 20%. PSCL 15% shows better sensitivity toward CO2 gas at room temperature. PSCL composites show complete reproducibility. The migration of electron between the p-n junction formed in the composite and concentration of SnCL4. 5 H2O in the PSCL composite make it sensitive toward exposed CO2 gas.