Construction Design Of Porous Zinc Oxide Nanomaterials And Its Sensor Applications

In recent years, with the speeding up of industrialization process, the increasinglyserious environmental pollution, people urgently need to be harmful to the toxic,flammable and explosive gases in real-time monitoring and control. In addition, thedrunk driving check in transportation and gas detection in a terrorist attack prevention,etc., are urgently needed to quickly identify the gas composition, Faced with thesethreats and challenges, the development of gas sensor has become the current relatedto the important part of human development, become one of the main topics of mutualinterest around the world. As a core part of gas sensor of gas sensitive material, theuse of the type and structure of sensor performance has important influence.Peoplethrough a variety of methods to improve the performance of gas sensor pieces, such asmetal doping, porous materials, and the development and design with porous structure,large specific surface area of the oxide semiconductor material,Is one of the effectivemeasures to effectively improve the sensor sensing properties, can significantlyincrease the specific surface area of materials of porous material, carrier mobility,porosity and permeability, to improve the sensitivity of gas sensors, response recoveryfeatures and detection limit plays an important role, we through the study of thestructure adjustment of zinc oxide semiconductor material, making the excellentperformance of gas sensor.In this thesis, we take ZnO as ths research object,and engage in the design andsynthesis of different morphology and structure ZnO micro-nano material based onhydrothermal synthesis method by adjusting the ratio of raw materials of precursorsolution and the pH of solution and adding surfactants, in order to improve thegas-sensitive property of ZnO micro-nano material， and making out the highperformance of gas sensor.The details are exhibited as follows.1.Synthesis of Crustose ZnO nanomaterial and its sensor research Crustose ZnO nanomaterials were synthesised by hydrothermal method. The gassensor sample was prepared using the crustose ZnO as a sensitive material, and thegas sensitivity of sensor samples was examined.The results show that the sensitivityof sensor sample is24.8and the response and recovery durations are2–3seconds,respectively. The concentration of acetone is100ppm at300℃. The gas sensitivity ofsensor samples to common interference gases was also examined, the results showthat the sensor possesses a superior selectivity to acetone.2.Synthesis of porous ZnO nanorods and ZnO nanorods and their sensors researchPorous ZnO nanorods and ZnO nanorods were synthesised byhydrothermal method. The gas sensor samples were prepared using the porous ZnOnanorods and ZnO nanorods as a sensitive material, The results show that thesensitivity of two kinds of sensor samples to100ppm ethanol gas were5.8and27.9at300℃respectively, they are4.8times as much, and it is3.1times to acetone gaswhich is the maximum sensitivity in the other gases under the conditions.and theresponse and recovery durations of porous ZnO nanorods gas sensor are4–10seconds.3.Synthesis of porous micro-spheres of ZnO and its sensors researchPorous micro-spheres of ZnO have been synthesized via a hydrothermal method.Gas sensors are fabricated from the ZnO porous micro-spheres and their gas-sensingproperties are measured. The results show that the sensor’soptimum working temperature was280℃, and the sensitivity of ZnO porousmicro-spheres sensors to50ppm acetone gas is26.8, and the response and recoverydurations are4–10seconds, respectively. Also, based on the gas sensitivity of porousmicro-spheres of ZnO sensor to other common gases were small,so, the sensorpossesses an excelent selectivity for acetone.