Study On Gas Sensitive Property Regulation And Mechanism Of Metal Doped MoSe₂

With the accelerating process of industrialization,a large amount of harmful gas emissions have caused serious environmental pollution and health problems.Therefore,finding efficient adsorbents to capture and remove these harmful gases has become an important task.In recent years,2D materials have become one of the hotspots in adsorbent research due to their unique structure and excellent properties.MoSe₂,as an important transition metal sulfide,has become one of the research hotspots in the field of adsorbents due to its excellent electronic transport properties and chemical stability.However,the adsorption capacity of MoSe₂ is limited,so doping it with other transition metal elements has become an effective way to improve its adsorption capacity.This research takes MoSe₂ as the base Material and uses Materials Studio 8.0 to simulate.The main research contents are as follows.1.The electronic structure properties of single-layer MoSe₂ and its adsorption capacity for different gases were studied based on density functional theory.The band structure of single-layer MoSe₂ was calculated and the bonding mechanism of Mo and Se atoms was analyzed through charge occupation and charge density maps.At the same time,five gases（CO,H₂S,NH₃,SO₂,and HCN）were selected,and the optimal adsorption positions were determined by optimizing the adsorption distance and molecular orientation.The adsorption properties of MoSe₂ monolayer on these gases were calculated,and the structural changes and partial wave state density of MoSe₂ monolayer after adsorption were analyzed.The results show that W and Se atoms lose electrons from Mo and gain electrons from Se during bonding.Monolayer MoSe₂ has certain adsorption capacity for HCN and SO₂,but weak adsorption capacity for other gases.In addition,the adsorbed monolayer MoSe₂exhibited different density of fractional wave states,indicating that the interaction between them and monolayer MoSe₂ was also different.The results show that the interaction of monolayer MoSe₂ on HCN and SO₂ is slightly stronger,but also weak for other gas molecular systems,and the adsorption effect is not obvious in general.2.The electronic structure and properties of Ta,Cu,Ni,W doped monolayer MoSe₂,the formation energy and energy band diagram of the doping system were studied.The adsorption properties,electronic structures and recovery time of the doped structures on CO,NH₃,SO₂,H₂S and HCN were calculated.The results show that the formation energy of the four systems is negative,which indicates that the reaction is spontaneous and the system is stable.Secondly,there is a certain degree of deformation in the Ta doping model.In addition,it is found through the band map that the impurity bands increase after doping,and the doping system of Ta,Ni and Cu basically belongs to P-type doping.The W-doped system has the tendency to change into metal.In addition,doping transition metal can significantly improve the adsorption capacity of MoSe₂ materials to the above gas molecules.For Ta and W doping adsorption system,HCN and CO adsorption effect is the best.The Ni doping adsorption system has the best adsorption effect on CO.Cu doping is most sensitive to NH₃ gas.At room temperature,only H₂S gas molecules can be desorbed normally,while for gas molecules with high adsorption energy such as SO₂,CO and NH₃,temperature rise conditions are needed in most cases for normal desorption.