ZIF-8 coated flexible carbon cloth substrates for CO2 sensing applications

Abstract

In this work, the application of Zeolitic Imidazolate Framework (ZIF-8) as a CO2 sensing material is investigated. The ball milling technique, a green and solvent-free alternative, was applied for synthesis and deposition on a sensing substrate, made of carbon cloth. The synthesized ZIF-8 via the ball milling exhibits excellent CO2 adsorption and detection characteristics, as demonstrated through fluorescence measurements with 82% reduction in fluorescence intensity upon CO2 exposure. To inspect the structural morphology, the crystallinity, and the pore size of the ZIF-8 sample, characterization tests including XRD, FTIR, BET, and FE-SEM were conducted. The characterization tests revealed the formation of a new phase of ZIF-8 (ZIF-L) using the ball milling procedure. Additionally, the MOF was coated on a carbon cloth substrate using ball milling at different milling speeds: 100 rpm, 300 rpm and 500 rpm. The MOF-coated substrates were characterized using SEM and EDS analysis to confirm the attachment of the MOF to the substrates. Gas chromatography tests were conducted to assess the capability of the coated substrates to absorb CO2. The sample, produced at a milling speed of 300 rpm, exhibited a favorable coating and CO2 adsorption with CO2 concentration reduction of 53.46%, thus, making it suitable for deployment as a sensing layer in miniature gas sensor.