Preparation Of Flower-like In₂O₃ Nanomaterials Doped With Metal Elements And Lts Gas Sensitive Properties

Formaldehyde is a toxic gas,which is widely present in people's production and life,and it is of great significance to the detection of formaldehyde gas.In2O3 is an n-type semiconducting metal oxide material with excellent gas sensitivity,but it still has problems such as high test temperature and low sensitivity when applied to formaldehyde detection.In order to solve these problems,the thesis used hydrothermal synthesis to prepare three-dimensional layered flower-like In2O3 nanomaterials,and modified the precious metal Pt and rare earth Er elements to characterize and analyze the morphology,structure,and chemical composition of the prepared materials.Test the gas sensitivity performance and analyze the gas sensitivity mechanism.The main work of the paper is as follows:(1)A three-dimensional layered flower-like In2O3 nanomaterial was prepared by hydrothermal synthesis.Its flower-like morphology is regular and neat,with a diameter of about 1?m,and a cubic crystal structure.The gas sensitivity test results show that the gas sensor based on three-dimensional layered flower-like In2O3 nanomaterials has a sensitivity of 24 to 50ppm formaldehyde gas at a working temperature of 1800C,showing good gas sensitivity to formaldehyde gas.(2)Three-dimensional layered flower-like In2O3 nanomaterials doped with precious metal Pt were prepared.The test results show that when the Pt doping concentration is lmol%,the gas sensitivity to formaldehyde is relatively optimal,and the sensitivity to 50ppm formaldehyde gas at a working temperature of 140? is 72,which is 3 times that of undoped In2O3 nanomaterials;The response time to 10ppm formaldehyde gas is 30s,and the recovery time is 44s,which has good response and recovery characteristics;in the long-term stability test,the sensitivity fluctuation range is within 5%,showing good stability.(3)The three-dimensional layered flower-like In2O3 nanomaterials doped with rare earth element Er were prepared.The test results show that thanks to the large specific surface area of the three-dimensional layered flower-like morphology and the doping modification of the rare earth element Er,the 3mol%Er-doped flower-like In2O3 nano-material gas sensor is resistant to 50ppm formaldehyde at a working temperature of 160?.The gas sensitivity is 112.Compared with the formaldehyde gas sensor reported in the existing literature,it has the characteristics of high sensitivity and low working temperature.It shows that 3mol%Er doped flower-like In2O3 nanomaterials have certain application potential in the field of formaldehyde gas detection.