First-Principles Studies On Gas Sensing Based On New 2D Metal Organic Framework And Traditional Metal Oxide

With the preparation of graphene in experiment,two dimensional?2D?has attracted extensive studies.Subsequently,a variety of two-dimensional materials have been discovered,including a new type of 2D metal-organic framework?MOF?materials,which have many excellent properties such as adjustable structure and function,large number of active sites and large specific surface area.The bright potential of 2D MOF materials is highlighted in some of the most important applications for gas storage and separation,optical,electric and magnetic materials,chemical sensing,catalysis,and biomedicine.In2016,a new 2D MOF material Au-1,3,5 triethynylbenzene?Au-TEB?framework,which has been recently synthesized by homocoupling reactions in experiments.Featured by C-Au-C linkages,2D Au-TEB network has a kagome lattice by Au atom and a hexagonal lattice by organic molecule within the same metal-organic framework?MOF?,which will have important application prospects in magnetic biomedicine,molecular sensor and apintronics.Moreover,the metal oxide semiconductor,MoO3,possess many excellent properties in gas sensing,for example large number of active sites and large specific surface area,has become a hot spot.In numerous experiments have been performed high sensitivity,good stability and selectivity for many gas molecule,especially trimethylamine gas.In this paper,using first-principles method,we studied the properties of gas sensing based on new 2d metal organic framework and traditional metal oxide.The calculated results will provide a theoretical reference and guidance for the two materials applying to gas sensing.The main research and results are presented as follows:?1?The geometric and electronic structure properties of Au-TEB have been systematically studied.By analyzed the electronic structure and spin-orbit coupling of Au-TEB,we found the Au-TEB is a magnetic and intrinsic half-metallicity 2D material,which is associated with the kagome lattice in Au-TEB hexagonal lattice.?2?We further studied the adsorption of F,Cl atoms,and small gas molecules including O₂,CO,NO₂ and NH₃ on Au-TEB network,aiming to exploit its potential applications in gas sensors.Adsorption of F or Cl atoms on Au-TEB can change the systems to nonmagnetic.The magnetic of the system can be efficiently tuned by NO2adsorbing on the Au-TEB.O₂,CO,NO₂ and NH₃ adsorbed on Au-TEB are both weak physisorption.Moreover,the results reveals that the resistivity can be improved through adsorbing those molecules,suggesting Au-TEB can detect those molecules.?3?Gas molecules?trimethylamine-TMA,dimethylamine,ammonia,benzene,toluene,acetone,acetaldehyde,formaldehyde,ethanol?adsorbed on the surface of MoO₃?010?surface are researched respectively.The results shows that compared with the perfect MoO₃?010?surface,the gas molecules have larger adsorption energy for MoO₃?010?surface with an oxygen vacancy.TMA has the largest adsorption energy no matter whether the MoO₃?010?has an oxygen vacancy or not,and have the improvement in the resistance characteristics after the surface adsorbed gas molecules.And the improvement is more visibly when MoO₃?010?surface has an oxygen vacancy.By the microscopic theory,we show the effect of the gas molecules adsorption on the structural,electronic properties of MoO₃?010?,which can detect those molecules.