PdO,Au,CdO修饰SnO_2纳米纤维的制备及其气敏特性

Preparation and Gas Sensing Properties of PdO,Au,CdO Coatings on SnO_2 Nanofibers

采用静电纺丝的方法制备了Sn O2纳米纤维,并分别用Pd O、Au、Cd O对该纳米纤维材料进行表面修饰.用X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线能谱(EDX)、X射线光电子能谱(XPS)分析、Brunauer-Emmett-Teller(BET)比表面积测试对材料进行表征.修饰前后,Sn O2纳米纤维都是由约15 nm的纳米颗粒构成的直径约为200 nm的多级结构材料.采用静态测试系统对纯Sn O2及不同物质修饰的Sn O2的气敏特性进行测试,结果表明,未修饰的Sn O2纳米纤维气敏元件对甲醛具有较好的响应.修饰后的Sn O2材料的气敏特性都有明显的改善.Cd O修饰的Sn O2气敏元件对甲醛的响应值最高,且响应恢复时间短,选择性好.Au修饰的Sn O2气敏元件对甲醛响应的最佳工作温度从300°C降到了200°C.经Pd O修饰后,Sn O2纳米纤维对甲苯的响应值变得最高.初步分析了经过修饰的Sn O2气敏材料的敏感机理.

Sn O2 nanofibers fabricated by electrospinning were coated with Pd O, Au, and Cd O. X-ray diffraction（XRD）, scanning electron microscopy（SEM）, energy dispersive X-ray spectrometry（EDX）, X-ray photoelectron spectroscopy（XPS）, and Brunauer-Emmett-Teller（BET） tests were used to characterize the nanofibers. The diameters of bare and coated Sn O2 nanofibers were approximately 200 nm, and had 15-nm diameter grains. The gas-sensing properties of all the nanofibers were characterized under static gas conditions. The results indicated that the bare Sn O2 nanofibers were sensitive to formaldehyde; however the sensitivity of the coated nanofibers was better. In particular, the Cd O-coated Sn O2 exhibited the highest sensitivity to formaldehyde, the shortest response and recovery times, and good selectivity. The operating temperature of the Au-coated Sn O2 decreased from 300 to 200 ℃, while the Pd O-coated Sn O2 exhibited the highest sensitivity to toluene. The sensing mechanism of the coated Sn O2 nanofibers was investigated.