Study On Gas Sensitivity Of Indium Oxide Based Nanoparticles To Ethanol Gas

The sensing performance of volatile organic compounds?VOCs?is always the research hotspot in the fields of hazardous gas detection not only for the toxicity impacts of VOCs with trace concentrations on human health,but also for their wide applications in health care,environment monitoring and industry processing.Among the various gas testing devices,metal oxide gas sensors?MOS?are important devices.Metal oxide semi-conductor-based gas sensors present high sensitivity with a fast response and recovery rate,small volume with low cost,and high compatibility in various applications.Therefore,it is very important to develop a high response gas sensor that can detect gases at low concentrations.Indium oxide?In₂O₃?has a direct band gap of about 3.6 eV and an indirect band gap of about 2.6 eV In₂O₃materials with different morphologies,such as nanoparticles,nanofibers,nanowires,nanotubes,nanosheets,and nanorods have received significant attention due to their potential applications for use in solar cells,photocatalytic applications,transparent conducting oxide and gas sensors.In₂O₃ is widely used as a sensitive material to detect gases,such as C₂H₅OH,CH₃COCH₃,CH₄,HCHO and CH₃OH.In₂O₃-based nanomaterials were mainly synthesized by solvothermal method,and their gas-sensitive properties to ethanol were studied.The main research contents are as follows:?.Synthesis of In₂O₃ nanomaterials at different calcination temperatures and their gas sensing properties.The precursor was prepared by solvothermal method,and then the precursor was calcined at different temperatures to obtain the named In₂O₃-500 nanoparticles.The structure and morphology of the product were characterized by XRD,TEM and other tests.When the optimal working temperature was 200°C,the sensor prepared with In₂O₃-500 nanoparticles exhibited excellent gas sensing performance for ethanol gas at ppm level,and had the characteristics of high sensitivity,good selectivity,and fast response.?.Facile synthesis of Pr-doped In₂O₃ nanoparticles and their high gas sensing performance to ethanolHigh-performance gas sensors should have the characteristics of high response capability,good selectivity,short recovery time,and relatively low operating temperature.Doping is an effective way to improve the performance of gas sensors.In this section,using ethanol as a solvent,Pr-doped In₂O₃ nanoparticles were synthesized by a one-step solvothermal method.The morphology and structure of the samples were characterized by X-ray powder diffraction,transmission electron microscopy,and X-ray photoelectron spectroscopy.The results showed that the prepared Pr-doped In₂O₃ nanoparticles had a size of about 10 nm and a specific surface area of 65.38 m²/g.Importantly,the 3 mol%Pr-doped In₂O₃ nanoparticles based sensor had efficient sensing performance for ethanol with a response value?106 at 50 ppm?,response time was 16.2 s,and a recovery time was 10 s at 240?,and these properties could maintain long-term stability.Therefore,the sensor was highly efficient sensing performance for ethanol.In addition,by testing six gases including ethanol,formaldehyde,methanol,acetone,benzene and ammonia,we found that the above sensor had good selectivity for ethanol.?.Preparation of Au-doped In₂O₃ nanomaterials and their gas-sensitive propertiesAu-doped In₂O₃ nanoparticles were prepared by a two-step method.In order to explore its potential application,a gas sensor based the nanoparticles was prepared and its gas sensing performance was tested.Compared with pure In₂O₃,the 1.0 wt%Au-doped In₂O₃ composite had the best sensing performance for ethanol gas with higher response,good selectivity,and shorter response recovery time at low operating temperature.At 200?,100 ppm ethanol was detected and the response value reached 600.Therefore,the precious metal Au-doped In₂O₃sensor had a good application prospect in the detection of ethanol gas.