(东北大学 资源与土木工程学院，沈阳 110819)
摘 要: 采用水热法制备不同Au掺杂浓度的分级多孔WO3微米球，探讨其作为气敏材料对NO2气体的气敏特性。利用XRD、SEM、EDS和XPS对制备的WO3微米球的晶体结构、微观形貌以及元素组成进行结构分析。结果表明：Au掺杂浓度对WO3微米球的结构和形貌没有明显影响，所获WO3微米球的直径均为3~5 μm，主要由直径为70~90 nm的六方相晶体结构的WO3纳米棒组成。在相同的检测条件下，Au掺杂浓度为2%(摩尔分数)时，WO3微米球可获得对NO2气体的最佳气敏反应特性，且在工作温度50 ℃时获得最大气体灵敏度，这主要是由于该Au掺杂浓度条件下获得的WO3微米球具有最小活化能的缘故。通过电子耗尽层理论和贵金属掺杂的化学效应对Au掺杂WO3微米球的气敏机理进行分析和探讨。
关键字: Au掺杂；WO3微米球；二氧化氮；气体传感器；气敏特性
（School of Resources and Civil Engineering, Northeastern University, Shenyang 110819, China）
Abstract:The hierarchical porous WO3 microspheres with different Au doping concentrations were synthesized by hydrothermal method and investigated as NO2 sensing materials. The crystal structure, morphology and element composition of WO3 microspheres were characterized by means of XRD, SEM, EDS and XPS measurements. The results show that the structure and morphology of WO3 microspheres are not significantly affected by Au doping concentration. The obtained WO3 microspheres with the diameters of 3-5 μm are assembled by numerous hexagonal nanorods with the diameters of 70-90 nm. 2% (mole fraction) Au-doped WO3 microspheres obtain the maximal response-recovery properties under the same conditions. The peak response is achieved at operating temperature of 50 ℃ for 2% (mole fraction) Au-doped WO3 microspheres, which is mainly due to its lowest activation energy. The gas sensing mechanism of Au-doped WO3 microspheres was discussed in accordance with the electron depletion layer theory and chemical sensitization of noble metal doping.
Key words: Au doping; WO3 microsphere; nitrogen dioxide; gas sensor; gas sensing property
