Preparation Of In₂O₃ And Other Metal Oxide Sensing Materials And Their Gas Sensing Properties

Recently,the growing attention to healthy life and environmental protection has generated great interest in efficient gas detection.The sensors based on semiconducting metal oxides are widely used in the gas sensing field owing to their low cost,good stability,high response,being easy to be integrated.Indium oxide?In₂O₃?,as a typical n-type semiconductor,has played a crucial role in detecting several toxic and volatile gases,including C₂H₅ OH,HCHO,CO,NO₂ and H₂S.In this case,We mainly investigate In₂O₃ material and try to solve the defects of the traditional In₂O₃-based sensor with high consumption and poor selectivity.Moreover,we also elementarily study some other semiconducting metal oxides such as stannic oxide?SnO₂?and zinc oxide?ZnO?.On the whole,the obtained research findings in this thesis are as follows:?1?Preparation of flower-like In₂O₃ microrods.Flower-like In₂O₃ microrods has been synthesized by one-step hydrothermal and subsequent calcination.Appreciable control on the morphology of as-synthesized In₂O₃ samples was attained by altering the weight ratio of glucose and urea.Furthermore,we describe a possible growth mechanism of this flower-like microstructure material.Finally,a systematical investigation of this sensor to ethanol is made.The flower-like In₂O₃ microrods-based sensor possess an excellent selectivity,a limit of detection lower to 1 ppm,and good repeatability.?2?Modification of flower-like In₂O₃ microrods.The in-situ dopant is carried out to modify the flower-like In₂O₃ microrods.And relevant characteristics show the Copper ions incorporate into the lattice of In₂O₃,which leads to an enhancement to nitrogen dioxide?NO2?sensing.2 mol% Cu-doped In₂O₃ exhibit better NO₂ sensing properties with a limit detection as low as 20 ppb and a marked selectivity,thus demonstrating potential applications in detection of NO₂.?3?Fabrication of SnO₂–ZnO composite hollow microfibers.SnO₂–ZnO composite hollow microfibers have been prepared by eletrospinning.And the sensing properties to acetone?CH₃COCH₃?are investigated.Compared with pure SnO₂ and ZnO microfibers,the sensor based on SnO₂–ZnO composite hollow microfibers presents superior sensingperformance,which could be mainly attributed to the hollow structure and interaction between SnO₂ and ZnO particles.