单斜相TiO2的制备及气敏性能

Preparation and Gas Sensitivities of Monoclinic TiO_2

采用简单水热法,制备出单斜相TiO2气敏材料,即TiO2(B)。利用丝网印刷法制备出气敏元件。借助于X射线衍射、扫描电子显微镜和透射电子显微镜分析材料的组织结构和形貌,研究了气敏元件在200～300℃对低体积分数H2的气敏性能。结果表明:经过180℃、18 h的水热反应,并在400℃烧结4 h能制备出较为均匀的TiO2(B)纳米纤维,纤维为实心结构,长度约为5μm,外径为30～50 nm。在300℃,随气体体积分数增加,气敏元件的灵敏度也随之增大,当H2的体积分数从1×10-6提高到100×10-6时,TiO2(B)的灵敏度从2升高到14。TiO2(B)对H2的灵敏度优于钛酸对H2的灵敏度。当温度从200℃升高到300℃时,TiO2(B)对体积分数为10×10-6 H2的灵敏度从1升高到13。

Monoclinic TiO2 nano-fibers [namely,TiO2（B）] were prepared by a simple hydrothermal reactions and gas sensors were prepared by a screen printing method.The micro-structure and morphology of the materials were characterized by X-ray diffraction,scanning electron microscope and transmission electron microscope.Gas sensing properties in a low H2 concentration at a tempera-ture range of 200-300 ℃ were investigated.The results show that the uniform and solid TiO2（B） nano-fibers can be prepared by hydrothermal reaction at 180 ℃ for 18 h and the subsequent sintering at 400 ℃ for 4 h.The length of the prepared TiO2（B） nano-fibers is 5 μm and the outer diameter of the fiber is 30 nm to 50 nm.The gas sensors become more sensitive to H2 with the in-crease of gas volume fraction.The sensitivity of TiO2（B） increases from 2 to 14 when volume fraction of H2 increases from 1 × 10-6 to 100 × 10-6 at 300 ℃.TiO2（B） has better gas sensing properties than titanic acid.Moreover,temperature has a great effect on the gas sensing properties.The sensitivity of TiO2（B） on H2 increases from 1 to 13 when temperature increases from 200 to 300 ℃.