SnO2纳米材料的制备及气敏性能研究-微电子学与固体电子学专业毕业论文

SnO2纳米材料的制备及气敏性能研究-微电子学与固体电子学专业毕业论文

5n02纳米材料的制备及气敏性能研究

一般Sn02纳米材料及本文中的Sn02纳米空心球，主要原因是该材料暴露的{1l 1)晶面具有很高的催化活性，有助于氧化还原反应的快速进行。

采用水热法合成暴露{332}高指数晶面的Sn02正八面体，Sn02{332}JE／＼面体棱长为95nm，两顶点间距离为140nm，在最佳工作温度250。C下，对800ppm 乙醇气体的灵敏度达2200，约为Sn02{111)最大灵敏度的12倍，且最佳工作温度低于Sn02{111)，响应恢复时间分别为1．5s和32s，气敏性能优于Sn02{111)八面体材料，原因是f332}晶面的催化活性高于{111)晶面，反应速率更快且最佳工作温度降低。

关键词：空心球；高指数晶面；气敏性能

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厦门大学硕士学位论文Abstract

Abstract

As the science and technology of modem society develop rapidly,living standards improves，at the same time，environmental pollution is also becoming more and more serious，including gas pollution．Thus gas sensors are used to monitor the environment gas and sound the alarm in time，which Can effectively solve the gas pollution problem．In a variety of gas sensors，the gas sensor of metal oxide semiconductor has high sensitivity,low cost，long life and other advantages．Combining with the nanotechnology further improve the performance of gas sensitive．Sn02 nano material is one of the most common used gas sensitive substrate materials，but in practical application there are still some shortcomings，like poor selectivity and11igh working temperature．Thus for the sake of further improving the gas sensor applications of nano Sn02 materials，reducing size of materials，doping and some other methods are used．Among these methods，changing the microstructures Can effectively increase the

the exposed high specific surface area，then increase the amount of target gas．Regulating

energy facets Can improve the surface reactivity of material，thus improve the reaction rate．In this study,two methods of changing the microstructures and regulating the exposed high energy facets to improve the performance of gas sensitive have been investigated．The connections between gas sensing a nd m icrostructure and crystal activity have also been explained．

One step hydrothermal synthesis without any template has been used to prepare

diameter of which are 1 40-200 nln．The Sn02 hollow

Sn02 hollow nanospheres，the

nanospheres are typically hierarchical structure，which consists of Sn02 nanoparticles．Compared with four kinds of organic gas as acetone，methanol，acetylene

and butane，the Sn02 hollow nanospheres shows excellent

selectivity to ethanol gas．At the optimal operating temperature of250。C，the sensitivity to 800ppm ethanol gas is 107，the response time is 1 2．3 S and the recovery time is 2 1．6 S．The reason for the better

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Sn02纳米材料的制备及气敏性能研究

gas —sensing performance of Sn02 hollow nanospheres is its larger surface area and

more nano scale channels ．

One step hydrothermal synthesis has been used to prepare Sn02 octahedral

nanocrystals with exposed h i 曲一energy{1 1 1)facets ．The side length

of t he octahedral Sn02{111)is between 150 and 250 nln ．Sn02{111)exhibited a maximum response

of 1 79 to 800ppm ethanol gas at the optimal operating temperature of 3 60。C with a

response time of 9．5 S and a recovery time of 6．7 S ．As a result of very hi

曲catalytic

activity of the{1 1 1)crystal face ，Sn02{1 1 1)has better gas-sensing performance ．

Hydrothermal synthesis has also been used

to

prepare Sn02 octahedral

nanocrystals with exposed hi 曲一energy{332}facets ，which have well-defined

octahedral shapes ．The length

is about 95 nln and the distance between two vertices is around 140 nln ．Octahedral Sn02{332}exhibited a

maximum response of 2200 at

250*C ，about 12 times to the response of Sn02{1

1 1)，with a response time of 1．5 S and a recovery

time of 32 S ．The catalytic activity of{332)facet is higher than{1

1 1) facet ，SO the gas-sensing performance of Sn02{3 32}is

better than Sn02{1 1 1)．

Key Words ：Hollow nanosphere ；Hi

曲一energy

facets ；Gas sensitivity ．

V