Regulation Of Gas Sensing Properties Of Carbon-based Nanomaterials And Its Application In Ozone Detection

Carbon nanotubes?CNTs?and Graphene?G?have attracted significant attention as a sensing element in chemical gas sensors.The unique structure of CNTs and G provides sensitivity and low detection limits for ambient gas species even at low temperatures.But there are still challenges in terms of selectivity,high sensitivity,and reproducibility,which can be achieved by functional modification with various components and doping to form a composite.Based on the potential value of CNTs and G in gas sensors.We have formed a chemical sensor array by non-covalently functionalized Multi-Walled carbon nanotubes?MWCNTs?and molybdenum disulfide?MoS₂?doped G to improve sensitivity and selectivity.Then forming a chemical sensor array with different recognition modes,which can be combined with image recognition and large data,In order to detect gaseous pollutants differently and rapidly through the in-depth development of the internet of thing?IoT?.?1?ThemodifiersofHydroxylaminehydrochloride?HONH₃Cl?,aminoaceticacid?C₂H₅NO₂?,succinic acid?C₄H₆O₄?,cetyltrimethylammonium bromide(C₁₉H₄₂BrN),8-hydroxyquinaldine(C₁₀H₉NO)and quinoline?C₉H₇N?were non-covalently adsorbed on the walls of MWCNTs by stacking interaction and van der Waals force.The sensor arrays based on non-covalent functionalized MWCNT were fabricated by coating the prepared sensing materials on ceramic substrates.The response to 5 ppm ozone?O₃?was increased by 68.8-258.3%and the maximum response was 34.4%.The maximum response of sensors based on functionalized MWCNTs to 100%relative humidity?RH?was just 5.6%,displaying the excellent endurance to humidity.After two months,the decrease in the response value of the most sensitive sensor to O₃ was no more than 15%,showing the good long-term stability.The sensor array was optimized according to principal component analysis,and the discrimination of six analytes was realized within 30 s at room temperature.The theoretical detection limits of O₃ for the most sensitive sensor in the sensor array were determined to be 46.8 ppb.?2?Ammonium molybdate(?NH₄?₆MO₇O₂₄·4H₂O)of 1,1/2,1/3 mmol and thiourea?CH₄N₂S?of 30,15,10 mmol were dissolved in 35 ml diluted Graphene oxide?GO?solution respectively.Transfer the solution to a 45 ml polytetrafluoroethylene?PTFE?autoclave and kept for 24 hours at 180^?C.Finally,different proportions of MoS₂/Reduced graphene oxide?RGO?composites were made into a simple sensor array.By detecting hydrogen peroxide?H₂O₂?,O₃,acetone?C₃H₆O?and ethanol?C₂H₆O?vapors,it was found that MoS₂/RGO-3 exhibited higher sensing response and faster response/recovery time to target gases.In addition,the three sensors based on MoS₂/RGO composites have good anti-interference performance for O₃,the identification of three target analytes in 14.5 s at room temperature was achieved,demonstrating its potential value in the detection of triacetone trioxide?TATP?precursors.