Preparation And Gas Sensing Properties Of Composite Materials Based On One-Dimensional CuO And ZnO Nanofiber

With the accelerated development of industrialization,the problem of environmental pollution has become increasingly prominent.Toxic and harmful gases produced by industrial production cause great harm to people's health.The semiconductor metal oxide gas sensor can use the redox reaction between the semiconductor material and the detected gas to cause the resistance of the material to change,thereby realizing the detection of the gas.Owing to semiconductor metal oxide materials have the advantages of easy availability,low cost,and stable chemical properties,which have been widely used in the detection of toxic and harmful gases.However,the current semiconductor metal oxide gas sensor still has some shortcomings,such as poor stability,low selectivity for detection gas,and high operating temperature.Therefore,it is particularly important to design and manufacture semiconductor metal oxide gas sensor materials with better performance.Among semiconductor metal oxides,zinc oxide?Zn O?and copper oxide?Cu O?materials often exhibit better gas-sensing properties due to their better physical and chemical properties and thermal stability.Compounding Zn O and Cu O materials or adjusting their morphology is a common method to improve the gas-sensitivity of materials.In this paper,one-dimensional Zn O/Cu O nanofibers heterostructure was prepared by electrospinning and subsequent calcination.By changing the ratio of zinc acetate and copper acetate in the precursor solution,five different ratios of one-dimensional Zn O/Cu O nanofibers were obtained.On this basis,firecracker-like and flower-like Zn O hierarchical structure materials were prepared by hydrothermal growth based on Zn O nanofibers.The gas-sensing mechanism of firecracker-like and flower-like Zn O graded structure materials was also studied.The specific research contents are as follows:?1?Polyvinylpyrrolidone?PVP?and different ratios of zinc acetate dihydrate?Zn Ac₂·2H₂O?and copper acetate monohydrate?Cu Ac₂·H₂O?were used as precursors to prepare solutions.Ratio of one-dimensional Zn O/Cu O nanofibers.X-ray diffraction?XRD?,scanning electron microscope?SEM?,transmission electron microscope?TEM?and energy dispersive X-ray spectrometer?EDX?were used to characterize and analyze the morphology,microstructure and composition of the sample.?Hydrogen sulfide,H₂S?gas is the target detection gas.The prepared Zn O/Cu O nanofiber sensor was systematically tested for gas-sensitivity,and the gas-sensitivity of one-dimensional Zn O/Cu O nanofibers with different ratios was explored.Studies showed that the construction of heterojunctions can effectively improve the gas-sensitive performance of materials.In addition,by adjusting the ratio of zinc acetate and copper acetate in the precursor solution and selecting the appropriate composition ratio,the gas-sensing performance of the one-dimensional Zn O/Cu O nanofibers can be effectively improved.?2?The firecracker-like and flower-like Zn O hierarchical structures were prepared by combining electrospinning and hydrothermal methods.First,Zn O nanofibers were prepared by electrospinning,and then the Zn O nanofibers were hydrothermally treated.Zn O nanorods are grown on the fibers to construct Zn O materials with firecracker-like and flower-like hierarchical structures.Among them,the firecracker-shaped Zn O hierarchical structure is prepared by directly hydrothermally treating the zinc oxide nanofibers,and the flower-like Zn O hierarchical structure is formed by placing the Zn O nanofibers in a hydrothermal solution for ultrasonic and hydrothermal treatment.The results show that the flower-like Zn O graded structure material has the highest sensitivity to H₂S gas and the fastest response time.In addition,the point-to-point contact between the Zn O nanorods that make up the flower-like Zn O hierarchical structure material helps to improve the gas sensing performance of the material.In summary,the main content of this paper includes the preparation of one-dimensional Zn O/Cu O nanofibers with different proportions by electrospinning,and the combination of electrospinning and hydrothermal methods to prepare Zn O hierarchical structure materials.In this paper,the gas sensing properties of the material were systematically tested,and the growth mechanism and gas sensing mechanism of the material were also studied.The research shows that the three-dimensional hierarchical structure material has better gas sensing performance than the one-dimensional nanofiber material.The gas-sensing performance of the material can be improved by constructing the heterojunction and controlling the morphology of the material.