Preparation Of Zinc Based Oxide Fibers And Its Gas Sensitive Characteristic

Along with the development of science and technology and industry,people's life is becoming more and more convenient.At the same time,the production of industry has made people more and more concerned about the environment of life.With the improvement of people's living material level,people are paying more and more attention to the living environment.In particular,paying attention to the air quality that must be breathed at any time.So it is very important to be able to detect the gas sensors in the atmosphere and the poisonous gases that have been brought into the interior.In addition,with the development of the information age,the Internet of things is also rapidly entering the people's life.The Internet of things plays an important role in transforming the different information of objects into electrical signals in the implementation of the sensor.In recent years,the metal oxide semiconductor based gas sensors hold great potential application in detection of toxic combustible gases,poisonous and hazardous gas due to the advantages of low production cost,simple fabricating technique and high sensitivity.As a direct wide band gap semiconductor metal oxide,ZnO shows excellent physical and chemical properties,becoming the focus of research as a promising sensitive material among a variety of semiconductors.Recent years have witnessed great progress in ZnO based gas monitoring devices.However,the main drawbacks of the gas sensing properties are poor sensitivity and selectivity,high working temperature.Thus,aiming at enhancing the gas-sensing properties of gas sensors based on ZnO,we focus on three aspects of synthesis method,doping and morphology.Their gas-sensing properties have been investigated systematically in this thesis.The main points of this thesis are summarized as follows:(1)Combing the features of electrospinning route and following annealing treatment.The ZnO-C nanofiber with 30.34 wt%carbon was prepared by a facial electrospinning route and following annealing treatment.The corresponding H2S gas sensors showed excellent selectivity and sensitivity compared to pure ZnO nanofiber gas sensors,particularly the sensitivity(102.13)to 50 ppm H2S.Besides,they exhibited a nearly constant response of approximate 40 to H2S at 20 ppm over 60 days.The superior performance of those H2S gas sensors can be attributed to protection of carbon to make sure the high stability of ZnO and the nanofiber to improve the sensitivity and selectivity to H2S.The good performance of ZnO-C gas sensor suggests that nanofiber composites prepared by a facial electrospinning route may provide a new research strategy in field of gas detectors,photocatalysts and semiconductor devices.(2)The nanofibrous material of ZnO-C like gourd type was prepared by electrospinning.The synthetic materials were characterized and tested by SEM and gas sensitive tester.The results show that the preparation technology can quickly and conveniently synthesize the nanofibers of gourd like ZnO-C under the temperature of 450.At 250 ?,it was the highest sensitivity to H2S and has excellent response.Moreover,compared with pure ZnO nanofibers,the synthesized ZnO nanofibers exhibit not only excellent gas sensing properties,but also good selectivity and high sensitivity.The complex is expected to be developed to produce a high performance H2S.