Synthesis Of Composite Oxide Sensor By MOFs Template Method And Gas Sensitive Performance

With the rapid development of social economy,it is an increased demand for gas sensing materials.Recently,metal-organic frameworks(MOFs)have attracted extensive attentions due to their open metal sites,adjustable coordination structures and high specific surface areas.MOFs as sacrificial templates of composite oxides for gas sensing,can produce specific morphologies,and improve the development of gas sensitivity.Therefore,this thesis mainly focuses on the composite oxide sensor prepared by MOFs as templates.The main research contents are as follows:(1)h-ZnO/ZIF-ZnCo_x core-shell structure composite material as the precursor,are converted into h-ZnO/Zn Cox under annealing,and further are detected TEA.The gas-sensing tests show that h-ZnO/Zn Cox has a high sensitivity to TEA,the highest sensitivity can reach up to 1020 exposure to 50 ppm TEA at 300oC,with a good linear fitting relationship,high selectivity and ultrahigh stability.Additionally,the influence mechanism of doping on the sensing is discussed in detail.(2)The CAU-17 microrods as template are transformed into hollow tubes by WO4^2-etching,and then into Bi2WO6 hollow tubes under annealing,and their conductivities are improved by Mg²⁺doping.The gas-sensing properties of cyclohexane are investigated for Bi2WO6 doped with different proportions of Mg²⁺.The test results show that the complex has a high gas-sensitive detection performance for cyclohexane,with a sensitivity of up to 64 towards 50 ppm cyclohexane at 250oC,which is the highest sensitivity result among all reported so far.Meanwhile,the composites also have a good catalytic performance on the degradability of potassium dichromate(K2Cr2O7)and rhodamine B(Rh B).(3)The Ce O2/ZnO nanosheets are synthesized using DIA(Zn Cex)as a sacrificial template.The effects of Ce⁴⁺doping on the n-octanol gas-sensitive properties such as sensitivity,selectivity and temperature are investigated.The composite shows a sensitivity of up to 679 for 50 ppm n-octanol at 225oC and exhibits ultra-high selectivity for n-octanol in alcoholic organic volatile gases.To our knowledge,this study is the first to examine metal oxides for the detection of octanol.