Research On Preparation And Properties For Inorganic Composite Gas-sensitive Material

With the development of society,men asking for materials are more and more exigent.Single material will no longer meet actual demand.Integration of two or more materials by chemical methods make it have the new property or have the advantages of both,that is where the superiority of the composite material is.In this thesis,with porous host materials modified or doped metal,we obtain univalent zinc in zeolite,zinc cluster in zeolite,and porous oxide doped with transition metals.This thesis mainly contains three parts as follows,the first part is introduction part,the second part and the third part are experimental ones.The first part introduction contains three issues:the first issue is definition and classification of gas-sensitive semiconductor materials,simply reviews the development of it, discusses the basic theory, and gives the basic requirement.The second issue talks about manufacturing and testing process of the gas sensor,and indroduce many kinds of distributing and testing methods.The third issue is about the introduction of porous composite materials,main introduce metal cluster in zeolite host-guest composite material.The second part is research on gas-sensitive properties of univalent zinc in zeolite and zinc cluster in zeolite.With zeolite Y and zeolite SAPO-44 as host materials,we make zinc vapour react with proton in zeolite by chemical vapor deposition and obtain univalent zinc@zeolite and zinc cluster@zeolite composite material.We produce our own reactor and succeed in reaction and testing of sample at oxygen and water free condition.By changing the zinc vapour content,we get a series of samples with different zinc content.Basing on the results of electron spin-resonance spectroscopy,we have form change of zinc cluster,and observe the ESR signal variances in inverse zinc evaporation at the same time and the change under UV irradiation.We conclude the function of UV irradiation is making the single electron transfer from the framework O to zinc.We also explore the in-situ interaction between ZnY and oxygen,water.ZnY and O2 produce O2-,with water we observe the split signal by aluminium,and attribute it to the structure.As the signal of ZnY is so wide,it is hard to observe and attribute signals,zinc in the SAPO-44 zeolite is better at this point.Interaction with oxygen,water,CO2,other organic gas,we observe all kinds of signals of them,also testing under UV irradiation.The third part mainly with n-butylamine as template,zincacetate form the precipitations under urea hydrolysis,heating at oxygen atmosphere,we get porous nano ZnO.By changing the content of Mn and Ni,perpare Zn/Mn,Zn/Ni oxide with different proportion.We have one Mn/Zn oxide sensitive to acetone and another Ni/Zn oxide sensitive to methylbenzene after gas-senor testing.We test the sensitivity of the two sample with different working current and get the best one.We study the adsorb-desorbs of the sample, prove it a sensitive,stable gas sensor.