Ultra-fast detection and monitoring of cancerous volatile organic compounds in environment using graphene oxide modified CNT aerogel hybrid gas sensor

Abstract

Ultra-fast detection of cancerous volatile organic compounds (VOCs) by carbon nanotube aerogel (CNT aerogel)-graphene oxide (GO) hybrid network has been studied in this paper. VOCs, especially non-polar compounds are difficult to detect due to their low electronegativity. A homogenous GO solution was drop cast on CNT aerogel film, both developed in-house, to obtain the CNT aerogel-GO composite. The CNT aerogel contains multi-directional porous CNT webs providing a stable and compact platform for GO adsorption. The loading concentration of GO and O/C ratios were optimized to obtain a highly sensitive CNT aerogel-GO hybrid sensor. The hybrid sensor could detect a range of non-polar VOCs like benzene, hexane, toluene, cyclohexane, and chlorobenzene with a limit of detection around 70 ppb. The optimized CNT aerogel-GO hybrid sensor showed 3 times better sensing performance than the bare CNT aerogel sensor. The principal component analysis (PCA) plot showed discrimination in all the VOCs as they all were distinct and spread over all four quadrants, indicating highly selective behavior of the sensor. Chemical and structural analysis by X-ray photoelectron spectroscopy and Raman spectrum showed that the oxygen loading could change the sp2 structure, making it ideal for sensing applications. The electron micrography images confirm the uniformity of the GO layer on the CNT aerogel. It is concluded that the concomitant formation of the CNT-GO junction can achieve better interaction and charge transfer during hybrid sensor fabrication. Subsequently, a sensitive, fast and durable CNT aerogel-GO hybrid sensor can be obtained for detection and continuous monitoring of cancerous VOCs.