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采用沉淀法制备了Fe2O3/MWCNTs复合材料。通过X-射线衍射分析(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)等测试手段对所合成材料进行了表征。结果表明,合成的Fe2O3/MWCNTs复合材料均由碳纳米管与氧化铁颗粒组成,Fe2O3粒子尺寸较均匀,其颗粒大小约为5 nm。在室温条件下,Fe2O3/MWCNTs复合材料对NOx具有较好的气敏性能,当NOx浓度为9.7×10-7时,复合材料对NOx的灵敏度为6.13%,响应时间为38 s。分析其原因主要是合成材料中Fe2O3的主要相态是呈p型半导体特性的γ-Fe2O3,与吸附空气中氧气呈现出p型半导体特性的MWCNTs复合时产生倍增效应的结果。
Fe2O3 / MWCNTs composites were prepared by precipitation method. The synthesized materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that the synthesized Fe2O3 / MWCNTs composites are composed of carbon nanotubes and iron oxide particles, Fe2O3 particles more uniform size, the particle size of about 5 nm. At room temperature, Fe2O3 / MWCNTs composites have better gas sensitivities to NOx. When the NOx concentration is 9.7 × 10-7, the sensitivity of the composites to NOx is 6.13% and the response time is 38 s. The main reason for the analysis is that the main phase of Fe2O3 in the composite material is γ-Fe2O3 which is a p-type semiconductor and results in a multiplication effect when it is combined with the MWCNTs whose oxygen in the air exhibits p-type semiconductors.