The Research Of WO₃,NiO And Its Composite Heterogeneous Nanocomposites' Gas-sensing Properties

With the development of Internet of Things(IOT),sensors,as the terminal equipment of IOT,are playing a more and more important role in the construction of IOT.Expecially the gas sensor is doing better in the field of environmental monitoring.Metal oxide semiconductor nanomaterials are paid much attention due to their excellent physicochemical propertyies and anisotropy.Nowadays,the research work about metal oxide semiconduct or nanomaterial has become a hot spot.In this paper,by using hydrothermal synthesis method,tungsten oxide(WO3)nanomaterial was made and then characterize it.The prepared WO3 nanomateria present to be plate-like,with its diameter about 250nm.After the performance test of the gas sensor,a series of test results about the plate-like WO3 nanomateria was taken and found out that it has better sensitivity towards NO2 under heating condition.By using hydrothermal synthesis method,the 80 nm plate-like NiO nanomaterial was prepared.Then,plate-like WO3 and NiO was compound at high temperature and then the Plate-like p-n heterogeneous NiO/WO3 nanocomposite was prepared.After the test to plate-like WO3,NiO and p-n heterogeneous NiO/WO3 nanocomposites nanomaterials' gas sensor in detail and got the related conclusion.Test results show that composite materials have better gas-sensing properties than two single materials and the tested gas has high selectivity.In nearly ten kinds of tested gases,Plate-like p-n heterogeneous NiO/WO3 nanocomposites only has a prominent response towards NO2 and the sensitivity of 30 ppm NO2 reaches 4.8.What's more,with the increase of concentration of NO2 gas,the sensitivity of composite material shows to be the approximate linear growth.Finally,we try to explain reasonably the experimental phenomena about the image of material characterization and gas sensor testing results by using the Principle of chemical adsorption on the surface of the material,the electronic gain and loss between gas and the Metal oxide semiconductor nanomaterials and the p-n heterojunction assumption.However,more experiments are still needed to prove speculation of PN junction theory.To sum up,this paper has developed a new direction in experimental idea and phenomenon explanation for the related research topic in the future.