In2O3/CdO复合材料的制备及气敏特性(英文)

Synthesis and Gas Sensitivity of In_2O_3/CdO Composite

采用水热合成方法制备了花状In2O3纳米材料.利用X射线衍射(XRD)、扫描电镜(SEM)、能量色散X射线光谱(EDX)及透射电镜(TEM)对材料的结晶学特性及微结构进行了表征.制备的In2O3材料呈现花状,是由粒径约20nm的椭球状小颗粒构成的分级结构材料.将制备的In2O3与纳米CdO以摩尔比1:1混合后,发现制成的In2O3/CdO复合材料经热处理后呈现葡萄状多孔结构.测试In2O3/CdO复合材料制作的气敏元件处于最佳工作温度(410°C)时,对0.05×10-6(体积分数,φ)的甲醛气体表现出较高的灵敏度.对比测试发现,In2O3/CdO复合材料制作的气敏元件对不同浓度甲醛的灵敏度明显优于纯花状In2O3纳米材料.同时In2O3/CdO复合材料制作的气敏元件在乙醇、甲苯、丙酮、甲醇以及氨气等干扰气体中具有对甲醛良好的选择性.讨论了In2O3/CdO复合材料气敏元件的敏感机理.

Indium oxide（In2O3） was synthesized using a hydrothermal process.The crystallography and microstructure of the synthesized samples were characterized by X-ray diffraction（XRD）,scanning electron microscopy（SEM）,energy dispersive X-ray spectroscopy（EDX）,and transmission electron microscopy（TEM）.The In2O3 had a flower-like hierarchical nanostructure and was composed of tiny near-spherical crystals with a diameter of approximately 20 nm.When In2O3 was mixed with CdO in a 1：1 molar ratio,it was found that the resulting In2O3/CdO composite showed an interesting grape-like porous microstructure following calcinations at elevated temperatures.A gas sensor using this In2O3/CdO composite as the sensing material showed higher sensitivity to different concentration of formaldehyde than the gas sensor based on pure flower-like In2O3 nanomaterials.The In2O3/CdO-based sensors showed a high sensitivity to a concentration of 0.05×10-6 formaldehyde at the optimized operating temperature of 410 ℃ and a good level of selectivity over other possible interference gases such as ethanol,toluene,acetone,methanol,and ammonia.The gas sensing mechanism of In2O3/CdO sensor has been discussed in detail.