Preparation And Characteristic Of ZnO And SnO₂ Nanometer Powders By Ultrasonic Atomization And Co-precipitation Method

In this paper, a novel method named ultrasonic atomization precipitation method was employed to synthesis the ZnO nano-powder and SnO₂ phosphor powders, based on the reviewing the research on the function, preparation and application of nanomaterials. The effects of the reaction time, the sintering temperature on the crystal morphology and size of ZnO and SnO₂ nano-powders were investigated; and the effect of the Eu3+ doping concentration on the luminescence properties of powder was discussed. Moreover, the phase and morphology of Ce doped SnO₂ particle size were carried out. The relation between gas sensitivity and the earth element was carefully measured. The details are summarized briefly as follows:1. At room temperature and normal atmospheric pressure, nano-ZnO powder was prepared by ultrasonic atomization and co-precipitation method with Zn(NO₃)₂ and (NH₄)₂CO₃ as raw materials. And focused study on the chemical processing condition of the zinc hydroxide dehydrated to ZnO nano-powder was carried out. The results show that the prepared spherical nanosized zinc oxide have narrow size distributions between 35 nm and 45 nm, moreover, the obtained nano-particles were more homogenous and have good crystallinity.2. Eu³⁺ doped ZnO powder was prepared by ultrasonic atomization and co-precipitation method using Zn(NO₃)₂, Eu(NO₃)₃ mixed solution. XRD, SEM and fluorescence spectrophotometer were employed to characterize the phase composition, particle size and luminescence property of powder obtained. And the effect of Eu³⁺ content on the emission intensity was investigated.3. The SnCl₄ solution or SnCl₄, Ce(NO₃)₃ mixed solution was transferred into the CO(NH₂)₂ solution via the ultrasonic atomizer, then the powder was calcined at different temperature. Finally, the nano-SnO₂ and Ce3+ doped SnO₂ powders were prepared. The effects of the reaction time and the sintering temperature on the morphology of SnO₂ nano-powder and size were carefully investigated. And focused study on the chemical processing condition of the tin hydroxide dehydrated to SnO₂ nano-powder was discussed.The results show that the prepared spherical nanosized SnO₂ have narrow size distribution between 10 nm and 20 nm. The gas sensitive elements were fabricated based on the obtained nano-powders. The relation of gas sensitivity between temperature, gas concentrations and doping element were measured. The investigations reveal that SnO₂ gas sensitive element has good response-recovery curves, higher sensitivity and lower operating temperature. And the introduction of Ce into SnO₂ nano-powder can improve its gas sensing characteristics obviously.