Laser Surface Modified Graphene And Gas Sensitive Properties Research

The development of society and technology has greatly increased the demand and consumption of energy,and produced a large number of by-products,such as part of solid waste,automobile exhaust and greenhouse gases,which have seriously threatened the ecological environment of modern society.Air pollution is a major factor that directly affects people’s quality of life and physical health.Therefore,it is of great scientific significance to develop a practical high performance gas sensor,and the sensitive material is the key to determine the sensing performance of the gas sensor,so the preparation of sensitive materials with excellent performance is an effective way to improve the gas sensitive characteristics of the sensor.Graphene is an ideal material in the field of gas-sensitive sensors because of its large surface area,high room-temperature carrier mobility and low electrical noise.In this paper,aiming at the existing problems of graphene,such as its inability to be mass-produced,complex preparation process,long response recovery time and low sensitivity,a strategy of surface functionalization treatment of graphene with laser micro-nano manufacturing technology was proposed,and a high performance graphene-based sensitive material was developed.Laser reduction of graphene oxide（LRGO）by direct writing technique was performed using a high degree of oxidation and thin lamellar graphene oxide（GO）as a precursor.The results show that the reduction degree of GO can be effectively regulated by changing the laser direct writing speed,so that the sensitivity and recovery time of the LRGO material can be taken into account simultaneously.Among them,the LRGO material obtained at 40mm/s direct writing speed has the best response-recovery characteristics,with a response value of 0.96 to 150 ppm NO₂ gas molecules and a response/recovery time of 130/198 s.On this basis,in order to further improve the gas-sensitive properties of the materials,ZnO/rGO composites were synthesized in one step by laser induced active precursor conversion reaction.The microstructure analysis shows that ZnO/rGO nanocomposites of different levels can be constructed by controlling the laser direct writing speed.Because of the synergistic effect between rGO and ZnO,the composite exhibits higher response value than LRGO.At 80 mm/s direct writing speed,the response value of the composite to 30 ppm NO₂ gas molecules can reach 5.32,and after 4 cycles of desorption cycle test,the performance of the composite has no obvious attenuation,and has good repeatability.