Research On Gas Sensors For VOCs Detection In Chemical Plants

With the accelerated development of industrial modernization,the volatile organic compounds（VOCs）produced by chemical plants continue to increase.VOCs,as the main pollutants in chemical plants,are highly volatile,toxic,and flammable.Once leaked,they not only seriously endanger people’s physical and mental health,but also cause serious environmental pollution.In order to avoid VOCs leakage incidents in chemical plants,it is crucial to quickly and efficiently detect them.Metal oxide semiconductor gas sensors are one of the important means to achieve VOCs detection,with simple structure,high sensitivity,low power consumption,and easy to make portable instruments.This article focuses on the design and development of metal oxide semiconductor sensitive materials for two typical VOCs gases,methanol and acetone,generated by chemical plants.Gas sensor devices are prepared,and their gas sensing characteristics and mechanisms are studied.A sensor device that meets the detection of typical organic volatile gases in chemical plants is obtained.The main research content includes the following two aspects:（1）A methanol sensor has been developed based on rare earth ion doped indium oxide material.A rare earth（RE=Er,Tm,Ho）doped In₂O₃ material was synthesized by solvothermal method,and its gas sensing performance was studied in detail.The experimental results indicate that the rare earth doped indium oxide material has a higher response to methanol gas and a lower optimal operating temperature.Among them,Er-doped In₂O₃ has the best gas sensing performance,with a response of 17.4 to methanol gas at a concentration of 50 ppm and a detection limit of 10 ppm,which has practical application prospects.（2）A acetone sensor was designed and developed based on Mg O doped Sn O₂ material.Mg O doped Sn O₂ materials were synthesized by a simple and cheap coprecipitation method.The gas sensing performance of Sn O₂ material sensors based on Mg O doping was studied,and it was confirmed that Mg O doping can improve the gas sensing response of Sn O₂materials to acetone gas.Among them,3%Mg O-Sn O₂ sensor has the best gas sensing performance,and the response value to acetone gas with a concentration of 50 ppm is 7.7,with good repeatability and selectivity.The sensing mechanism is also analyzed in detail.