Research Of In₂O₃-based Nanomaterials For Modification And Gas-sensing Performance

At present,the increasingly severe air pollution has threatened our living environment.Mankind faces unprecedented environmental challenges.Among them,gases such as formaldehyde and triethylamine in the air are fatal to human body.Relevant researchers have developed a variety of detection technologies,aiming to conduct a micro-assessment of these toxic and harmful gases,enhance public health consciousness and ease the economic burden of diseases caused by excessive emission of detrimental gases.However,the current sensors still leave much to be desired.Such performance parameters as selectivity,sensitivity,temperature and humidity tolerance restrict the development of formaldehyde and triethylamine sensors towards practical applications.Therefore,research on gas-sensitive materials with excellent performance is particularly crucial to development of sensors.This thesis aims to synthesis In₂O₃ with different morphologies such as nanoparticles,micro-nanotubes by hydrothermal and oil bath methods,and develop a practical nanomaterial like formaldehyde and triethylamine through modification approaches such as doping and loading metals,so as to overcome the problems of high working temperature,humidity effect and long-term stability caused by gas poisoning and other factors.Meanwhile,we simulated the real-time environment,gained deep insight into the gas-sensing mechanism,and advised the development of a new type of gas-sensing material system with excellent performance and low cost.Related research works was summarized as follows:(1)Fabricating Ag nanoparticles sensitized In₂O₃ nanograins gas-sensing material.The In₂O₃ nanograins structures are synthesized via simple hydrothermal strategy,the nanograins size is small and there are no by-products.After loading the Ag nanoparticles,the working temperature of the material is significantly reduced to room temperature due to the catalytic effect of Ag.The 5%Ag-In₂O₃ nanoparticles shows a response of 135 to 1 ppm formaldehyde gas at the best working temperature of 30°C,and exhibits poor response to other interfering gases at the same temperature.(2)Constructing Platinum-supported Cerium-doped hollow hexagonal microtubes In₂O₃ gas-sensing material with good antihumidity.This work mainly involves the morphology design of MOF In₂O₃ using terephthalic acid as the ligand acid through an oil bath reaction and subsequent annealing,and then the hollow hexagonal In₂O₃microtubes materials are prepared successfully.Modification of hexagonal In₂O₃microtubes are obtained by Ce doping and Pt loading.Compared with pure In₂O₃ and Ce₁₂In,1%-Pt/Ce₁₂In shows the superior gas performance to TEA at lower operating temperature(180°C)with high response(1110 for 10ppm TEA),humidity independence,fast response speed and long-term stability.