Study On Improving Gas Sensitivity Of Nanospheres And Micro-Flowers Hybrid ZnSnO₃ With Multi-measures

Gas sensor can detect specific gases in the environment,and it is widely used in the detection of flammable,explosive,toxic and harmful gases.Gas-sensitive materials have a vital influence on the performance of gas-sensitive sensors.Among many gas-sensitive sensors,MOS gas-sensitive sensors are highly concerned at home and abroad due to the gas-sensitive materials have advantages of prepared easily,environmental friendly and excellent gas-sensitive performance.ZnSnO₃ is a ternary metal oxide semiconductor with perovskite structure.It combined the advantages of both Zn O and Sn O2 materials,showing excellent gas-sensitive performance.However,like many binary metal oxide semiconductor materials,ZnSnO₃ gas sensor needs to work at more than 200?to achieve good gas sensitivity performance,and its gas sensitivity performance is relatively poor at a lower temperature,which seriously limits its application.In view of these problems,the following measures were taken to improve the gas sensitivity of ZnSnO₃ at low temperature in this paper:firstly,Under the action of the organic functional additive Triethanolamine(TEOA),ZnSnO₃ composed of micro-and nano-sized particles with high specific surface area were prepared by coprecipitation method;secondly,Mg doped ZnSnO₃,doping can enhance the gas sensing activity of ZnSnO₃ and improve the gas sensitivity response;finally,The UV-sensitive material nano-Ti O2 decorated ZnSnO₃ to form heterojunction,which reduced the working temperature of ZnSnO₃under the auxiliary irradiation of ultraviolet light.Gas sensitivity test showed that when the molratio of Mg/Zn was 1:9 and the modification amount of Ti O2 was 10 wt%,Ti O2/Zn0.9Mg0.1Sn O3 composite have the best gas sensitivity performance:under ultraviolet light(5 W,365 nm),the response value of the gas sensitivity material to 500 ppm ethanol gas was as high as 149.81,and the corresponding working temperature was 80?.The reasons why Mg can improve the gas-sensitive performance of ZnSnO₃ are as follows:the weak electronegativity of Mg changes the chemical adsorption and desorption of Zn and Sn atoms in ZnSnO₃ to oxygen and oxygen ion species,improves the activity of gas-sensitive materials,and thus increases the gas-sensitive response.In addition,the UV-photosensitive material Ti O2 and ZnSnO₃ form heterogeneous junction at the interface,which can increase the number of electrons in the ZnSnO₃ conduction band under ultraviolet light,which is conducive to the generation of more oxygen ion species and the occurrence of gas sensitive reaction,thereby reducing the gas sensitive working temperature of ZnSnO₃.In conclusion,a kind of ZnSnO₃ composed of micro-and nano-sized particles with two different morphologies was prepared in this study.The Mg-doped and UV-photosensitive material Ti O2 modification not only reduced its working temperature,but also improved its gas sensitivity.The preparation of the above special morphology ZnSnO₃ and the improvement of gas sensing performance provide a new idea for the research of high-performance gas sensors.