基于真空冷冻干燥法ZnO纳米粉体的制备及其气敏性能研究

Preparation of ZnO Nano-powders via Vacuum Freeze-drying Approach and Studies of Its Gas Sensing Properties

为了探索真空冷冻干燥技术对制备ZnO气敏材料的应用价值,采用此方法制备了PVA-Zn(CH_3COO)_2·2H_2O泡沫板状前驱体,再分别以不同温度煅烧前驱体制备了ZnO纳米粉体,并将产物制成旁热式气敏元件。对产物进行XRD、SEM和TG-DSC表征并详细探讨了产物的气敏性能,结果表明纳米ZnO粉体的粒径随着煅烧温度的降低显著缩小,气敏性能显著升高。在500℃煅烧冷冻干燥前驱体得到的ZnO粉体平均粒径为40～100 nm,在工作温度为440℃时对300 ppm乙醇的灵敏度可达51.43。

In order to research the application of the vacuum freeze-drying approach in the flied of preparation of gas sensitive materials such as ZnO nanomaterials,the approach was applied to prepare PVA-Zn(CH 3COO) 2·2H 2O solid foams precursor,ZnO nanometer powders were prepared by calcining the precursors at different temperatures,and the products were made into a by-thermal gas sensor.The product was characterized by XRD,SEM and TG-DSC,and its gas sensitivity was discussed in detail.The results showed that the particle size of nanometer ZnO powder decreased significantly with the decrease of calcining temperature and the gas sensitivity increased significantly.The products obtained from 500 ℃ heating treatment have an average size of 40~100 nm,and the sensitivity to 300 ppm ethanol was up to 51.43 at the working temperature of 440 ℃.