激光蒸凝法制备过渡金属氧化物纳米粒子研究.pdf

一一一一一一一一一一一一一一鲤型三丝q全学位论文激光蒸凝法制备过渡金属氧化物纳米粒子的研究摘要犷429342 付犯 0 本文采用激光蒸凝法,以Co (AC),·4H20, Cu (AC),·H2O、金属Zn 为靶材,150W CW C02激光器为光源,成功地制备出了Co/Coo, Cu/Cuo, Zn/ZnO纳米粒子;采用EDTA滴定分析、透射电镜(TEM)、电子衍射(ED), x一射线衍射(XRD)、振动磁强计(VSM)、等技术对纳米粒子的化学组成和性能进行了表征;探讨了实验参数对纳米粒子性能和产率的影响。」在制备co/coo纳米粒子的实验中,结果表明:激光功率密度、反应压力、载气种类及流量等工艺参数对产品的粒度、晶型等性能均有影响。激光功率密度越高,反应区温度越高;反应压力越低、载气流量越大,获得粒子的粒径越小;在惰性气氛、氧气气氛和氢气还原气氛下,产物均为Co和coo的混合物,但其钻含量不同,平均粒径约为 15nm,磁饱和强度为51. 96emu/g,矫顽力为614 De。在制备Cu/Cu0纳米粒子的实验中,结果表明:激光功率密度、反应压力、载气种类及流量等工艺参数对产品的粒度、晶型等性能同样有影响。在惰性气氛下,产物主要是Cu和Cu20,粒径为10-30nm;在氧气气氛下,产物主要是Cu, Cu'O和Cu0的混合物,粒径为10-50 nmo 在制备Zn/ZnO纳米粒子的实验中,结果表明:制备工艺条件对形成的纳米粒子有一定的影响,反应压力和载气流量影响纳米粒子的形貌。不同的反应气氛制备的产物不同,在惰性气氛下产品纳米粒子是 Zn和ZnO的混合物;而在氧气气氛下,所得的纳米粒子是纯ZnO;在氢气气氛曳得到较纯的z“纳米粒子。总之,(采用激光蒸凝法,。备过渡金属氧化物纳米粒子具有反应可控,产物纳米粒子具有粒径小、分散性好的优点,并且该法工艺简单、相对其它物理方法产量大、成本低,具有较好的工业应用前景。此外,在粒子的经典成核理论的基础上,针对纳米粒子的形成过程的三个阶段,应用热力学和动力学有关理论探讨了制备工艺参数对形成的粒子粒径的影响,获得了一些初步的结论。关键词:激光化学,纳米粒子,co/coo,Cu/Cuo,’Zn/ZnO 北京化工大学硕士学位论文 STUDY ON THE PREPARATION OF METAL OXIDE NANOPARTICLES BY LASER HEATING GAS-EVAPORATION METHOD Abstract Co/Coo,Cu/CuO, Zn/ZnO nanopartiles were prepared by Laser heating gas- evaporation method with Co(AC), Cu(AC)2·4H20 or Zn as the targets respectively, and a laser of 150W CW C02 as the light source. Complexo-metrictitration of EDTA, Transmission electron micros- copy (TEM), electron diffraction patterns (ED), X-ray-diffraction (XRD) and vibrating-sample ometer (VSM) were used to describe the characteristics of these samples. The effects of process parameters on the nanoparticles have been pilot studied. The results of preparation of Co/COO nanoparticles show that the more powerful laser power, the higher reaction temperature; the size of the particles is small as the pressure is low and the rate of carrier gas is high; and different content of the nanoparticles is the result of the different reaction gas. It is als