Preparation Of Pt-MoSe₂ Microsensor And Study Of NO₂ Gas Sensing Characteristics

With the development of social economy and the expansion of industrial production scale,the impact of human activities on the atmospheric environment is becoming increasingly serious,especially for industrial and agricultural production based on chemical raw materials.Air pollution is becoming increasingly serious,and NO2,as a typical air pollutant,has been intensively studied.Due to its great harm to the air environment and human health,it is of great significance to conduct efficient and convenient routine detection of atmospheric pollutant NO₂.Traditional NO₂ sensors have problems such as large structure and volume,which are not conducive to integration,high operating temperature,and large heating power consumption.They cannot meet the portability requirements of NO₂ detection in today’s society.In this paper,metal Pt hybrid MoSe₂ powder was synthesized as a sensitive material to prepare a micro gas sensor for low temperature,low power consumption,and low concentration detection of NO₂ gas.MoSe₂ is a new type of two-dimensional semiconductor material,which is different from high-temperature gas sensitive detection characteristics such as metal oxides Sn O₂ and Zn O.This material can achieve good gas sensitive response characteristics at lower temperatures,and has the characteristics of low concentration and high selectivity.The limitation of low sensitivity can be improved by doping metal Pt,which is conducive to the detection of NO₂ by the sensor.In this paper,based on MEMS technology,a ceramic based micro hot plate gas sensor has been designed and fabricated.The sensor has the advantages of small size,low power consumption,corrosion resistance,and strong anti-interference performance.In this paper,ANSYS software is used to carry out finite element simulation experiments on the thermal structure of ceramic based microsensors,and calculate the thermal structure and thermal stress coupling characteristics at thermal steady-state,verifying the rationality of the microstructure and the feasibility of the process.The two-dimensional MoSe₂ sensitive material was synthesized by hydrothermal method,and the material modification was studied through metal Pt hybridization.The microstructure and particle size of the material were obtained through characterization and analysis of Pt-MoSe₂ material by SEM,XRD,and TG,and the crystalline structure and composition of the material were verified.A micro gas sensor was fabricated on a ceramic micro hot plate electrode using a thick film method,and a gas sensing test platform was built to test the gas sensing characteristics of toxic and harmful gases such as NO₂,CO,SO₂,ethanol,and ammonia.The test results show that the prepared micro gas sensor has good gas sensitive response characteristics to 0-20ppm NO₂ at an operating temperature of110℃and a power of 40m W,achieving a minimum detection limit of 0.1ppm NO₂concentration.The sensor has a sensitivity of 1.35 to 10 ppm NO₂ gas,and a response recovery time of 180s and 608s.Pt metal hybridization can significantly improve the conductivity of the sensor,while significantly improving the sensitivity and response rate.