【作者】 陆晓晶；

【导师】 魏先文；

【作者基本信息】 安徽师范大学 ， 无机化学， 2005， 硕士

【摘要】 一维纳米材料具有新奇的电学、光学、磁学、热学和化学性质,在太阳能电池、传感器、催化剂、吸附剂和选择分离等重要领域有广泛的应用前景。因此,一维纳米材料的制备与性能研究在现代材料科学的研究中具有非常重要的地位,是材料科学的前沿领域之一。在众多的制备方法中,氧化铝模板法已成为制备一维纳米材料最为有效的方法之一。多孔氧化铝模板因具有高孔隙率、耐高温、绝缘性好、模板容易制备、合成方法简单及在模板孔中形成的纳米管和纳米棒易从孔中分离出来等特点而倍受人们青睐。本论文旨在利用氧化铝模板孔道作为微反应器,建立室温下制备纳米棒（管）的一种简便方法, 探究沉淀法制备一维纳米材料的条件、结构及性能之间的关系,为制备新型功能性低维纳米材料奠定基础。1.以氧化铝膜作为模板,尝试BaCl₂ 与Na₂SO₄ 溶液分别在膜的孔道两边通过室温下沉淀反应制备BaSO₄纳米管,产物经透射电子显微镜（TEM）及选区电子衍射（SAED）、扫描电子显微镜（SEM）和X-射线粉末衍射仪（XRD）表征,表明生成了直径为200-350 nm,长度为30 μm 的BaSO₄单晶纳米管,与氧化铝膜的孔径及厚度相符。2.利用氧化铝膜与经5% H₃PO₄ 中35℃下扩孔15 分钟的氧化铝膜作为微反应器,用BaCl₂与Na₂WO₄溶液在室温下反应48 h 获得了直径为200-350 nm 及350-450 nm,长度达30 μm 的BaWO₄ 单晶纳米棒。经透射电子显微镜（TEM）及选区电子衍射（SAED）、扫描电子显微镜（SEM）及电子能谱仪（EDX）、X-射线粉末衍射仪（XRD）和拉曼光谱（SRS）表征,结果表明BaWO₄ 纳米棒的直径可通过模板的孔径来控制,同样改变反应时间（从48h 分别改变为28h 或12h）,都制备了BaWO₄ 纳米棒,表明制备BaWO₄ 纳米棒的沉积时间只需12 h。3.尝试使用氧化铝膜作为微反应器制备稀土卤化物低维纳米材料,LnCl₃ 或Ln（NO₃）₃ 与NaF 溶液在氧化铝膜的孔道内室温反应可制备稀土氟化物（氟化铕、氟化镧与氟化铽）纳米管或纳米棒。产物经X-射线粉末衍射仪（XRD）、透射电子显微镜（TEM）、扫描电子显微镜（SEM）及x-射线能谱仪（EDX）和高分辨透射电子显微镜（HRTEM）等手段进行了表征。通过改变反应时间、反应物的浓度探究了合成稀土氟化物的低维纳米材料的规律,结果发现反应时间长（48 h）可得到纳米棒,反应时间短（24 h）可得到纳米管;同样反应物浓度大（0.05 mol/L）时得到纳米棒,浓度小（0.02 mol/L）时得到纳米管,这表明化学法沉淀时也是从氧化铝膜内的孔壁开始沉积的。更多还原

【Abstract】 A great deal of attention has been paid to one-dimensional nanomaterials due to their novel electrical, optical, magnetic, thermal and chemical properties. They have significant potential applications in many fields, such as solar energy conversion, chemical sensor, catalysis, absorption and separation. So, research on the preparation and properties of one-dimensional nanomaterials are one of the most exciting areas in materials science. Among the different fabrication methods, using porous alumina as template is one of the most widespread methods to synthesize one-dimensional nanomaterials, because porous alumina membranes have high pore density, thermal stability, good insulating properties and are easy to prepare, and the products formed in it are easy to be separated. The goal of the thesis is to investigate the relationship among the synthesis conditions, structures and properties of one-dimensional nanomaterials obtained by precipitation method using alumina membrane as a nanoreactor. The method provided a simple and convenient way for preparing nanotubes or nanowires at room temperature, also established the base for the preparation of novel functional nanomaterials. Firstly, We tried to prepare BaSO4 nanotubes using porous alumina membrane as the template,Ba²⁺（BaCl₂） and SO₄^2- （Na₂SO₄） would enter the pores of the alumina membranes and form nanotubes. The products were characterized by transmission electron microscopy （TEM）, selected-area electron diffraction （SAED）, scanning electron microscopy （SEM）, and X-ray powder diffraction （XRD）. The results indicated that the products were single crystal BaSO₄ nanotubes with outer diameters of 200-350 nm which correspond to the pore diameters of alumina membrane, and length up to 30 μm which correspond to the thickness of the alumina membrane used. Secondly, BaWO₄ nanorods were prepared by reaction of aqueous solutions of BaCl₂ with Na₂WO₄ for 48 h using porous alumna membrane and widened alumina membrane as templates, which were characterized by transmission electron microscopy （TEM）, selected-area electron diffraction （SAED）, scanning electron microscopy （SEM）, energy-dispersive X-ray spectrometer attached to the field emission scanning electron microscopy （EDX）, X-ray powder diffraction （XRD） and stimulated Raman scattering （SRS）. The diameters of the BaWO₄ nanorods could change from 200-350 nm to 350-450 nm when the pores of alumina membrane were widened by 5 wt% H₃PO₄, which indicated that the diameter of BaWO4 nanorods could be controlled by the pore diameter of alumina membrane. It is noted that the reaction time for the BaWO₄ nanorods formed was 12 h only. Thirdly, We tried to prepare rare earth fluoride nanomaterials with length over 10μm using alumina membrane as a reaction vessel. Ln³⁺ （LnCl₃） and F^-（NaF） would enter the pores of the alumina membranes and form rare earth fluoride nanotubes or nanorods （EuF₃, LaF₃ and TbF₃）. The products were characterized by X-ray powder diffraction （XRD）, transmission electron microscopy （TEM）, scanning electron microscopy （SEM）, energy-dispersive X-ray spectrometer （EDX） attached to the field emission scanning electron and high-resolution transmission electron microscopy （HRTEM）. It is found that nanorods could be obtained with long reacting time （48 h） or high concentration, while nanotubes were obtained with short reacting time （24 h） or dilute concentration, which suggested that the deposition of the precipitants also started at the pore wall of alumina membrane.更多还原