离子液体中纳米材料的合成与研究

【作者】 汤汝兰；

【导师】 徐存英；

【作者基本信息】 昆明理工大学 ， 材料学， 2008， 硕士

【摘要】 纳米材料因其优异的光、电、磁和化学性能越来越受到人们的关注。纳米材料的制备方法很多,但随着人们环境意识的提高,简便,无污染的纳米材料的制备方法依然是人们追求的目标,而室温离子液体正好满足这些要求。本文选用离子液体作为反应介质来制备铝化合物、SiO₂、镍的配合物三种纳米材料。我们利用扫描电子显微镜（SEM）、X射线衍射、N₂吸附等一系列分析测试手段,对合成的纳米材料的形貌、结构及物相进行了表征;并讨论了反应参数对纳米材料微结构的影响。主要内容如下:1.制备并提纯了氯代1-丁基-3-甲基咪唑[C₄mim]Cl,1-丁基-3-甲基咪唑四氟硼酸盐[C₄mim][BF₄]两种离子液体。2.以[C₄mim][BF₄]离子液体为溶剂,氯化铝为原料,采用溶胶-凝胶法来制备铝化合物纳米材料,并对得到的产物进行了一系列表征。结果表明:得到的产物Al₄O₂Cl₁₀·xH₂O,其形貌为厚度约为4-15nm的片状结构。采用XRD研究了反应温度,NaOH的浓度、原料等因素对产物的影响。另外,采用溶剂热法合成出了单斜晶系的Al（OH）₃,同时考察了温度对产物的影响。3.以[C₄mim][BF₄]为溶剂,硅酸乙酯为原料,采用溶胶-凝胶法制备无定形态的纳米SiO₂时,表面活性剂和热处理对产物的形貌、粒径、比表面积有影响。没加表面活性剂得到的SiO₂为一些比较分散的球形小颗粒,粒径在6-20nm左右,比表面积为132.8m²/g,添加了表面活性剂得到的SiO₂为海绵体结构,粒径在25nm左右,比表面积为156.4m²/g。经550℃煅烧后得到的产物粒径分别为30-50nm和12-25nm左右。同时研究了[C₄mim]Cl离子液体、凝胶温度对纳米SiO₂的影响。4.以[bmim]BF₄离子液体和水为混合溶剂,采用化学沉淀法制备了镍的化合物。用XRD、TEM对产物进行了结构和形貌表征,结果表明:经60℃恒温反应24h,可制备出镍的有机配合物Ni（C₄N₂H₆）₆（BF₄）₂,其形貌为不规则的多面体结构,长为1.4μm左右。生成镍的有机配合物的原因是离子液体不纯,在纯的离子液体中我们得到的产物为六方晶体的β-Ni（OH）₂,其形貌基本呈球形,粒径在5μm左右。采用XRD研究了反应温度,原料的浓度等因素对产物的影响。另外,采用溶剂热法也制备了镍的有机配合物,用XRD、TEM等现代分析测试手段对产物进行了结构和形貌表征,结果表明:经150℃恒温反应6h得到的镍的有机配合物呈棒状,棒的直径约为4.1μm,长度约为10-12μm。采用XRD研究了反应温度对产物的影响。更多还原

【Abstract】 Nanomaterials have received considerable attention due to their novel properties such as electronic,magnetic and chemical properties.There are many methods used to prepare nanomaterials,but it is still needed to improve a facile,environment-friendly route for synthesis nanomaterials with growing concerns over the environmental impact.Ionic liquids are environment-friendly solvent.Al compound,SiO₂ and nickel compound nanomaterials were prepared in ionic liquids.The samples were characterized by XRD, SEM,IR,N₂ adsorption techniques.The effects of reaction factors such as temperature, content of raw material on grain size,morphology,crystalline phase of the products were investigated.The following main contents can be summarized as following:（1）1-butyl-3-methylimidazoliumchloride[C₄mim]Cl and 1-butyl-3-methylimidazolium tetrafluoroborate[C₄mim][BF₄]have been synthesized and purified.（2）Nanostructured Al compound was synthesized using ionic liquid[C_mim][BF₄]as solvent by means of sol-gel.The samples were characterized by XRD、SEM and so on.The results show that the Al₄O₂Cl₁₀·xH₂O was obtain,and its morphology is of platelet with the size of 4-15nm.We investigated effects of temperature,raw material and content of NaOH on products.The monoclinic Al（OH）₃ was obtained by means of Solvothermal method, the effect of temperature on mirostructure of the products was also investigated.（3）Silica nanoparticles was synthesized in[C₄mim][BF₄]by means of sol-gel.The samples were characterized by XRD,SEM and N₂ adsorption.The results show that the microstructure of SiO₂ are influented by surfactant and heat treatment.The particle size is ranged from 6-20nm and the specific surface area is 132.8m²/g for spherical SiO₂prepared without surfactant,while the average grain size is 25nm and the specific surface area is 156.4m²/g for spongelike SiO₂ prepared in the present of surfactant.After calcinations at 550℃,The particles size was increasing,up to 30-50nm for spherical SiO₂ prepared without surfactant,and The particles size of SiO₂ prepared with surfactant changed instinctively. The effects of temperature and ionic liquid on Crystalline phase of SiO₂ were investigated（4）Nickel compound was synthesized using the mixture of ionic liquid[C₄mim][BF₄] and water.The morphologies and structure of nickel compound are characterized by XRD,TEM and so on.The results indicated the nickel compound wih 1.4μm in length was obtained.The possible formation causation of nickel compound was due to impurity of ionic liquid.In order to proof this idea,β-Ni（OH）₂ with diameter of 5μm was obtained using ionic liquid purified.The effects of content of raw material and temperature on products were investigated.Solvothermal method was employed to prepared nickel complex,nickel complex with rod was obtained when the reaction temperature is kept at 150℃for 6h,the length and the diameter of rods isl0-12μm,4.1μm,respectively.The effect of temperature on microstructure of products was investigated.更多还原