Physisorption mechanism in a novel ionogel membrane based CO2 gas sensor

Abstract

The steadily increasing concentration of carbon dioxide (CO2) gas in the atmosphere is a significant environmental problem in modern society. Henceforth, there is triggering interest in the new technological solutions for CO2 monitoring. This work reports the fabrication of a novel, low cost, chemiresistive carbon dioxide sensor based on the PVA/[EMIM][SCN] based ionogel membrane. Here, the lightweight transparent ionogel membrane with enhanced ionic conductivity is acted as the electrically conductive region of the sensor. The response rate of the CO2 sensor was monitored in terms of direct as well as alternating current resistance using a high-precision multimeter and an impedance spectroscopy, respectively. The CO2 desorption kinetics were also studied to check the reliability of the sensor using the conductometric approach. The selectivity of the sensor for CO2 gas was well evidently quantified by comparing the response rate of the sensor with both CO2 and N2 gases. The optical microscopic images were periodically taken before and after CO2 exposure in conjunction with the conductivity data revealed the physisorption mechanism of the sensor. The upshots presented herein will promote the development of an organic CO2 gas sensor, which will be worthwhile for numerous industrial and practical applications and for air quality control in the future.