Structural Regulation And Gas Sensing Properties Of Cobalt Tetroxide-based Composites

People’s living standards in our country are gradually improving with the booming economy,and they pay more and more attention to the health of the body and the surrounding environment.The gas sensor is a kind of sensing equipment used to sense and detect gas.It has a wide range of applications for automobile exhaust emissions,industrial toxic gas concentration measurement,and household gas leak detection.There are many types of materials used for gas-sensing detection.Among them,metal oxide semiconductors stand out due to their unique advantages,but their high-temperature operation and poor selectivity requirements limit practical applications.In recent years,in order to further enhance its gas sensitivity,researchers have adjusted some of its influencing factors such as morphology,lattice defects and other factors.From the morphology point of view,the flower-like Co₃O₄ microspheres we prepared have a large specific surface area due to their unique morphology.The gaps formed between a large number of randomly distributed nanosheets facilitate gas penetration and diffusion,and at the same time provide a large number of active reaction sites for gas adsorption.This article starts with flower-shaped cobalt tetroxide,and then modifies and modifies it on this basis.The paper discusses the existing gas-sensing mechanism in detail,and also provides some ideas for the development of some new gas-sensitive materials.The specific work of this paper is as follows:1.With the goal of preparing sensitive materials with special morphology,flower-like cobalt tetroxide was designed and synthesized by hydrothermal method and subsequent calcination method.Through specific characterization,the relationship between the morphology and performance of the material and the gas-sensing mechanism were discussed in detail in terms of its morphology,chemical bonds and defect oxygen content.The test results show that the prepared flower-shaped cobalt tetroxide microspheres exhibit a good gas sensitivity response of 72.3%and good selectivity to 100 ppm nitrogen oxide at room temperature.The flower-like morphology solves the problems of gas diffusion and small specific surface area,and provides enough space for the adsorption of oxygen and the transfer of electrons.As a result,the sensitivity of the spherical flower-like material is greatly improved compared with the material with irregular morphology prepared by the traditional method.2.The Ag/Co₃O₄ composite material was designed and synthesized,which kept the original flower-like morphology.The overflow effect of precious metals promotes the material to have excellent gas sensitivity to heptanol.The doping amount of silver of different precious metals has an important influence on the gas-sensing performance of the material.A proper amount of silver doping can avoid agglomeration and provide an overflow effect so that more oxygen can be adsorbed to the surface of the material.The gas sensor operates at room temperature and has a good gas sensor response.It has great application potential in industrial agriculture and daily life.