水热法制备稀土元素复合氧化锌及其气敏性能

Synthesis of ZnO Powder Mixed with Rare Earth by Hydrothermal Method and Its Gas Sensing Properties

采用水热法制备了ZnO粉末和复合不同稀土离子的ZnO粉末,并通过X射线衍射谱(XRD)和扫描电镜(SEM)进行了结构和形貌表征,结果显示,ZnO材料具有六方纤锌矿的结构,稀土离子以氧化物的形式析出,纯ZnO及稀土复合的ZnO均为棒状。由气敏测试结果可看出,Sm离子的复合使纯氧化锌对甲醛、乙醇和三甲胺的灵敏度得到明显提高。Sm2O3-ZnO复合材料对1.0×10-4(体积分数,下同)的甲醛的灵敏度达到58.04,对1.0×10-3的甲醛的灵敏度达到959.60。在7种气体的干扰下,Sm2O3-ZnO复合材料显示了良好的选择性。该材料对甲醛的灵敏度是对丙酮、甲醇和乙醇的灵敏度的4倍左右。另外,Sm2O3-ZnO复合材料在300℃对1.0×10-4甲醛的响应时间和恢复时间分别为17 s和12 s。

ZnO and ZnO powders mixed with different rare earth ions were prepared by hydrothermal method. Their structures and morphologies were characterized by XRD and SEM. The results indicate that pure ZnO material exhibits hexa- gonal wurtzite structure, and rare earth ions have been formed as oxides. The morphologies of ZnO and ZnO powders mixed with different rare earth ions are rods -like structures. The gas sensing results shows that Sm3＋ - composition improves the sensitivities of pure ZnO to formaldehyde, ethanol and trimethylamine gases. The sensitivity of Sm2 03-ZnO ＂composited materi- al obtains 58.04 to 100ppm formaldehyde. The sensitivity of the composited material obtains 959.60 to 1000ppm formalde- hyde. In the interference of seven gases, Sm2 03-ZnO composited material exhibits excellent selectivity. The sensitivity of the material to formaldehyde is about four times the sensitivity to acetone, methanol and ethanol. In addition, the response time and recovery time of Sm203-ZnO composited material are 17 s and 12 s towards 100ppm formaldehyde at 300℃, respectively.