Preparation Of TiO₂-based Nanorod Array And Research On Its Gas-sensing Properties

The controlled synthesis and assembling of TiO₂ nanorod array by liguid-phase chemical route is investigated in this paper.The preparation,formation mechanism and properties of array materials are discussed.The paper mainly focuses on the architecture and properties of novel array structure,to illustrate the relationship between array morphology and their gas sensing properties.1.TiO₂ nanoparticle film is employed as seed layer for the hydrothermal growth of dense,uniform of TiO₂ nanorod arrays on the substrate.The nanorods are smooth with the average diameter of～65 nm and the length of～1μm.The nanorod arrays assemble to the device surface by the same experimental method and gas-sensing properties of the materials were measured.The results indicated that the TiO₂ nanorod arrays sensors exhibit excellent sensing property to Triethylamine（TEA）.The sensitivity of this film sensor to 100 ppm TEA at 290℃was 14.2,the response of 2 s,the recovery time of162 s and a low detection limit of 0.1 ppm.2.The as-prepared TiO₂ nanorod arrays were used as substrate.MoO₃/TiO₂nanorod arrays were prepared by second hydrothermal method.MoO₃ evenly dispersed on the surface of TiO₂ nanorod array.Compared to the pure TiO₂ nanorod arrays,The sensitivity have improve twice,the sensitivity of gas sensor to 100 ppm TEA at 290℃was 30,the ultrafast response and recovery characteristics to 100 ppm TEA was 1 s and256 s,and low detection limit of 0.01 ppm.3.The NiO/TiO₂ nanorod arrays were prepared by second hydrothermal.Ni O nanosheets with star-shaped like grown on the top of TiO₂ nanorod.The sensor exhibits high sensitivity and selectivity to TEA.The gas selectivity was explained by the catalytic effect of nanosheet NiO and the extension of the electron depletion layer via the formation of p-n interface.The working temperature is reduced by 40℃.The sensitivity of the sensor to 10 ppm is 6.29.Compared to the TiO₂ nanorod arrays,it has improved 2.3 times and the reponse time of 1 s,the recovery time 86 s,and low detection limit of 0.001 ppm.