Room temperature resistive gas sensor based on ZIF-8/MWCNT/AgNPs nanocomposite for VOCs detection

Metal organic frameworks (MOFs) are a group of hybrid organic–inorganic materials with high surface area and porous structure, which recently have been considered in gas sensing studies. This research is a unique report on application of ZIF-8, a well-known MOF, as sensing material in a resistive gas sensor for detection of some volatile organic compounds (VOCs) at room temperature. ZIF-8 was synthesized and composited with MWCNTs and Ag nanoparticles to obtain a semiconductor sensing material for detection of some VOCs including methanol, ethanol, acetone, acetonitrile and n-hexane at room temperature. In order to investigate the sensor performance, the main sensor parameters such as sensitivity, reusability, repeatability, response/recovery time and stability were evaluated. Because of high surface area of ZIF-8 (1360 m²/g) and its nanoporous structure, sensor exhibited good sensitivity to the analytes. Furthermore, the most sensitivity of sensor was observed for ethanol and methanol due to small size of these molecules. In addition, sensor responses were fast and all measurements showed repeatability. Contrary to metal oxide sensors that are used under high temperature, this sensor works at room temperature. To the best of our knowledge, this is the first report on using this nanocomposite of ZIF-8 as sensing material in fabrication of resistive gas sensor for detection of VOCs.