Monitoring of CO2 using MWCNTs functionalized clay porous composite for clean room facility

Abstract

In this current work, a vastly sensitive, selective, and cost-effective CO2 gas sensor was developed by utilizing MWCNTs doped clay ceramics, for the developments in clean room facilities or pharmaceutical purposes. Herein, MWCNTs functionalized clay composites (CTsX; X = 0, 5, 10, and 15) were prepared by a bottom up approach i.e. solid-state reaction method and characterized by SEM with EDAX, XPS, XRD, FTIR, UV–visible spectroscopy, BET, and sensing. SEM micrographs revealed the created pores and grown nanotubes within the base material. XPS demonstrated some sites of Oads deficiencies, attributed to the expediting of sensing phenomena. Further, MWCNTs are well functionalized with clay as confirmed via XRD phases such as SiO2 (trigonal), AlKSi3O8 (monoclinic), Al2CaSi2O8 (triclinic) and C2Ca5Si2O13 (monoclinic). Furthermore, BET established the mesoporous nature of CTs15 composite having mean pore size ∼ 3.82 nm, also CO2 gas (200–1000 ppm) was tested at ambient temperature. Moreover, CTs15 composite showed maximum sensor response (S.R.) 5.31 at 1000 ppm of CO2 gas, whereas minimum response/recovery time (Tres./Trec.) 10.87/8.93 s were noticed at 200 ppm while operated at 28℃ (ambient condition). Additionally, LOD assured 217 ppm, which suggests that fabricated sensor is highly sensitive and selective for CO2, and may be used for clean room services. Therefore, this cost effective and eco-friendly composite is suitable for monitoring of CO2 gas for indoor and outdoor environments within a few seconds of Tres. and Trec..