基于高岭土多孔基板的In2O3微米梳制备及其气敏性能

采用模压-烧结法制备高岭土多孔基板,考察烧结温度对高岭土多孔基板表面形貌与孔隙结构的影响,通过热蒸发法在高岭土多孔基板上制备出In2O3微米材料,并采用XRD、SEM、FTIR、阿基米德排水法等检测手段考察多孔基板及In2O3微米材料的形貌与结构。结果表明,在烧结温度1 200℃时所获高岭土多孔基板的孔径尺寸在45μm左右,显气孔率为32.71%,体积密度为1.48 g/cm^3,抗弯强度为15.08 MPa。在该多孔基板上所制备的In2O3产物呈梳状结构,梳齿直径和长度分别在1~10μm和20~80μm范围内,梳柄长度约为1 mm,结晶良好。对In2O3微米梳的气敏检测结果表明:In2O3微米梳对NO2气体具有良好的选择性、可逆性和重复性;其对浓度为0.001%的NO2气体的灵敏度随着工作温度的升高呈先升高后降低的趋势,响应时间和恢复时间随之减少,且在最佳工作温度200℃时达到最大值,为44.4,此时的响应时间和恢复时间分别为21 s和106 s;In2O3微米梳对NO2气体的灵敏度随着NO2浓度的增加而增加,两者之间呈线性相关,响应时间随着NO2浓度的增加而缩短,恢复时间则随之增长。

Preparation and Gas Sensing Properties of In2O3 Microcombs Grown on Kaolin-based Porous Substrates

The kaolin-based porous substrates were prepared by press molding-sintering method， and the surface morphology and porestructure of kaolin-based porous substrates prepared at different sintering temperatures were investigated. In₂O₃ micromaterials were synthesized on the surface of kaolin-based porous substrates by thermal evaporation method. The morphology and structure of kaolin-based porous substrates and In₂O₃3 micromaterials were investigated by XRD， SEM， FTIR and Archimedes drainage method. The results indicate that the optimal kaolin-based porous substrate at the sintering temperature of 1 200 ℃ shows the pore size of approximately 45 μm， the apparent porosity of 32.71%， the bulk density of 1.48 g/cm3， and the flexural strength of 15.08 MPa. In₂O₃ products prepared on the substrate has a comb structure with good crystallinity.The diameter and length of comb finger are in the range of 1~10 μm and 20~80 μm， respectively， and the length of comb handle is about 1 mm. Gas sensing results show that the In₂O₃ microcoms has good selectivity， reversibility and repeatability for NO₂ gas. Its sensitivity to NO2 concentration of 0.001% gas increases first and then decreases with the increase of operating temperature， and response time and recovery time reduced with increasing operating temperature. The maximum of the sensitivity of 44.4 was obtained at an optimum operating temperature of 200 ℃. The response time and recovery time are 21 s and 106 s， respectively. There is a linear correlation that the sensitivity of the In₂O₃ microcombsincreases with increasing NO₂ gas concentration. The response time is shortened as the NO₂ concentration increases， and the recovery time increases as the NO₂ concentration increases.