Research On NO₂ Gas Sensor Based On SnO₂/SnSe Heterostructure And Its Performance

NO₂gas is ubiquitous in daily life due to its toxicity and irritation.Inhalation of NO₂gas can damage the body's respiratory tract.For example,motor vehicle exhaust and chemical fuel combustion artificially produce a large amount of NO₂.It can also cause acid rain to damage the natural environment.Therefore,developing and designing highly sensitive sensors at room temperature to detect low-concentration NO₂gas is necessary.It is worth mentioning that composites with heterostructure have significant advantages in gas sensitivity.The heterostructure can accelerate the charge transfer,increase the carrier concentration,expose more active sites,increase the specific surface area,and reduce the grain boundary barrier.It shows strong interactions between passing through heterogeneous interfaces with superior sensing performance than a single material.Therefore,this paper uses heterostructural composite materials'preparation,characterization,and gas sensitivity properties.The main work is as follows:(1)Polygonal sheet SnS₂was prepared by hydrothermal method and then oxidized in situ to form a SnO₂/SnS₂composite.The material was characterized and gas-tested to explore the influence and advantages of its N-N type heterostructure on sensing properties.The results showed that the SnO₂/SnS₂-3 samples showed high sensitivity and rapid response recovery by comparing the different in situ oxidation times of SnS₂.(2)The SnO₂/SnSe₂heterojunction materials were synthesized using the hydrothermal method.SnO₂particles modify sheet SnSe₂to form an N-N type heterostructure.SEM,TEM,XRD and I-V characteristic curves were also used.Testing of the sensing performance was performed.The SnO₂/SnSe₂-35 sample showed better sensitivity and reduced the operating temperature by comparing the sensing performance.(3)By regulating base concentration,SnO₂/SnSe heterostructural composites were grown in situ by a one-step hydrothermal method.SnO₂/SnSe nanosheets composites were prepared by regulating the alkali concentration to control the self-assembly rates of SnSe nanosheets while forming defect point oxidation.SnO₂/SnSe nanosheets used as a highly sensitive sensor for the detection of NO₂at room temperature.The as-obtained SnO₂/SnSe materials were characterized by SEM,XRD,TEM,XPS and I-V polarization to analyze the relationships between the heterogeneous structure morphology,crystallography,chemical components,electrical properties,and sensitivity mechanism.