Research On Construction And Sensitive Properties Of Transition Metal Diselenide-Based Gas Sensor For Flammable Gas Detection

With the advancement of science and technology,combustible gas as a highly efficient energy source is increasingly used in human daily life and industrial production.However,due to its flammable and explosive characteristics,there are also huge safety hazards.The leakage of flammable gas will endanger human health and cause poison or cancer,etc.Dangerous accidents such as explosion caused by it will lead to serious economic losses and threaten the safety of human life and property.Therefore,it is extremely important to detect flammable gas quickly and efficiently.Based on the transition metal diselenide nanocomposite film,an ethanol gas sensor based on Ti O₂/WSe₂,a hydrogen sulfide sensor based onα-Fe₂O₃/Mo Se₂,a benzene gas sensor based on Au-Zn O/WSe₂and a Pd-WSe₂based carbon monoxide gas sensor were constructed in this thesis.The hydrothermal method,metal organic framework（MOF）derivation,liquid phase exfoliating and other methods were used to prepare metal oxides,transition metal diselenides and so on.Layer-by-layer self-assembly technology（Lb L）,screen printing technology and so on were adopted to prepare high-performance combustible gas sensors for various combustible gas detection.The XRD,SEM,TEM,XPS,BET and other characterization methods were used to observe and analyze the element composition,microscopic morphology,crystal plane and lattice,atomic valence,and specific surface area of the gas-sensitive thin film.By building static and dynamic gas distribution test platforms,the dynamic switching response,repeatability,selectivity,response/recovery time and long-term stability of the sensors were examined.The influence of humidity on the response performance of the sensors was also explored.Furthermore,combined with first-principles simulation calculation based on density functional theory（DFT）,from the perspectives of oxygen adsorption and desorption on the metal oxide surface,increased surface area and active adsorption sites,synergistic effect of composite film heterostructure and catalysis of noble metals,the sensitive mechanism of flammable gas sensor based on transition metal diselenide was revealed.In this thesis,high-performance transition metal diselenide-based flammable gas sensors were constructed for the detection of ethanol,hydrogen sulfide,benzene and carbon monoxide,and the gas sensitivity and sensing mechanism were studied,which opens up new application fields for thin-film gas sensors based on transition metal diselenide,and provides certain theoretical guidance and engineering reference for the development of combustible gas sensors.It also has important reference value for the accurate and rapid detection of combustible gases and the development of new combustible gas detection devices.