铈掺杂WO_3纳米材料气敏特性研究

Study on gas sensing properties of Ce-doped WO_3 nanomaterials

以金属W粉为原料采用溶胶—凝胶法制得纳米级WO3粉体,探讨了不同CeO2添加量对气敏特性的影响。CeO2掺杂WO3材料对挥发性有机化合物(VOCs)气体灵敏度有显著提高,而器件的工作温度有所降低。FE—SEM测试结果说明:CeO2掺杂对晶界的移动形成某种"钉扎"效应,使晶粒减小,比表面积增大。复阻抗谱分析认为,Ce4+主要存在于晶界,使晶界电阻增大,晶界电容减小,提高了WO3材料的气敏特性。

Nano-scaled tungsten-trioxide （WO3 ） powder is synthesized by sol-gel process using tungsten powder as material. The effect of cerium oxide（ CeO2 ） additive on the sensitivity of final devices is investigated ,especially to volatile organic compounds （VOCs） and significant enhancement is achieved,the highest sensitivity is found to shift to low heating voltage. The analysis from field-emission SEM reveals that grain boundary is pinned due to adding CeO2,which results in decrease in the average grain size of Ce-doped WO3 and increase in the surface area, compared with the undoped ones. Complex impedance spectroscopy analysis indicates that the Ce ions mainly exist in WO3 grain boundary, which results in increase in grain boundary resistance and decease in grain boundary capacitance. The gas-sensing property of WO3nanomaterials is improved.