W掺杂ZnO纳米线型矿业安全用NO2气敏材料研究

NO2 Sensing Materials Based on W-doped ZnO Nanowires for Mining Safety

以二氯化锌(ZnCl2·2H2O)、碳酸钠(Na2CO3)为前驱体,钨酸钠(Na2WO4·2H2O)为钨源,采用水热法制备不同W掺杂浓度的ZnO纳米线,并对其结构形貌和NO2气敏性能进行研究。利用X射线衍射(XRD)和扫描电子显微镜(SEM)对样品的结构性能进行表征,表明W掺杂浓度对ZnO纳米线的结构和形貌基本没有影响,所获产物为直径50~80 nm、长度2.0~5.2μm的六方纤锌矿结构ZnO纳米线,其表面光滑,结晶度优良,分散性良好。针对NO2的气敏特性结果表明,W掺杂浓度为1%时,ZnO纳米线可获得对NO2气体的最大灵敏度,其最佳工作温度为200℃,且具有优良的选择性、可逆性和重现性。通过电子耗尽层理论和反应活性位点对气敏机理进行了分析和探讨。

W-doped ZnO nanowires were synthesized by a hydrothermal method using zinc dichloride(ZnCl2·2H2O)and sodium carbonate(Na2CO3)as the precursor,as well as sodium tungstate(Na2WO4·2H2O)as the tungsten source.The microstructural characterization by means of X-ray diffraction microscopy(XRD)and scanning electron microscopy(SEM)showed that the structure and morphology of ZnO nanowires were not affected by W doping.The obtained products with diameter of 50~80 nm and length of 2.0~5.2μm were ZnO nanowires with hexagonal wurtzite structure,which possessed smooth surface,high crystallinity,and good dispersion.NO2 sensing measurements indicated that 1%W-doped ZnO nanowires achieved the highest sensor response at an operating temperature of 200℃and good selectivity,reversibility and reproducibility.The gas sensing mechanism was discussed in accordance with the electron depletion layer theory and reactive site.