Study On The Trimethylamine Gas Sensing Performance Of Vanadium Oxide And Vanadium Nitride

With the improvement of human living standards,people are gradually realizing the impact of human activities on the environment.Gas sensors are devices that change the resistivity of materials in different gases,the development of sensitive materials with excellent performance is an important part of the development of gas sensors.Metal oxide semiconductor materials have been widely used as an important gas sensor sensitive material.However,some other sensitive materials are also being developed.Nano-synthesis technology is one of the important methods to prepare sensitive materials.In the exploration of developing excellent sensors,it is necessary to regulate the microstructure,gain size,morphology and composition of sensitive materials.With the development of nanotechnology,it has provided greater possibilities for the preparation of high performance gas sensors.In this thesis,vanadium-based oxide and nitride were prepared by simple hydrothermal synthesis combined with annealing and ammonia reduction.The gas sensing properties for detecting toxic and harmful gas trimethylamine were studied.The main contents of this paper are as follows:1.Spherical V₂O₅ three-dimensional hierarchical structure was synthesized by hydrothermal method,following annealing VOOH precursors process in air,spherical V₂O₅ three-dimensional hierarchical structure is composed of single crystal nanosheets.The growth period of the spherical morphology is proposed according to the Ostwald ripening principle and the anisotropic growth mechanism.The prepared spherical V₂O₅ exhibits good selectivity to trimethylamine at a working temperature of 240°C,and rapid response recovery time,good stability.Its good gas sensitivity is closely related to the three-dimensional hierarchical structure,and its gas-sensing mechanism is explained by chemisorption process.2.Flower-like porous VN nanomaterials was synthesized by reducing VOOH precursors under low temperature in ammonia gas.The thermal stability of the materials was analyzed before gas sensing test.At the working temperature of 230°C,the VN nanoflowers exhibit the properties of the N-type semiconductor in trimethylamine.Comparing the same concentration of other gas showed a higher response to trimethylamine,and rapid response recovery time.The gas sensing properties of the prepared materials are related to the unique microporous structure,and the gas sensing mechanism is explained according to the adsorption desorption model.