【作者】 关瑶；

【导师】 官建国；

【作者基本信息】 武汉理工大学 ， 材料学， 2010， 硕士

【摘要】 氧化铁材料由于成本低廉,环境污染小,抗腐蚀性和稳定性强等特点,在催化剂、颜料、磁记录介质、磁性涂料、气体传感器以及生物等领域应用广泛。目前液相合成氧化铁纳米材料的方法虽然很多,各具优势,但也都存在一些缺陷。探索设备简单、操作方便、成本低、产率高的液相合成方法,以实现对纳米材料形貌、尺寸、结构的选择性控制,仍然是化学家和材料学家长期以来关心的课题之一。本论文用简单、低成本、绿色的液相法制备了不同形貌的氧化铁纳米材料,并研究了纳米结构的形成机制以及相关的物理化学性能。在酸性环境中,控制反应温度获得了不同形貌的α-FeOOH/α-Fe2O3纳米粒子。产物的形貌对反应温度有强烈的依赖性,在高温下易于得到纳米棒,而低温下易于形成层片堆积的1D纳米结构。与纳米棒状结构相比,层片堆积的1D纳米结构α-Fe2O3具有更高的比表面积(129.16 m2/g)和更优异的光催化性能。在紫外光照射180 min后能有效地将罗丹明降解为其他小分子。利用空气氧化法制备出纯相的Fe304纳米粒子,研究了空气的流速、反应温度、反应时间、碱含量对其形貌和结构的影响规律。同时发现当KN03作为氧化剂时,可以得到形态规则的八面体状的Fe304纳米粒子。在无还原剂、表面活性剂、硬模板得条件下,采用溶剂热法,通过控制反应温度,获得由小颗粒组装成的磁性空心微球。碱、次亚磷酸二氢钠、水的含量对空心球的产生起着重要的作用。与160℃的产物相比,在200℃获得的磁性空心球由于晶粒尺寸的差异而具有更高的饱和磁化强度Ms (80.17 emu·g-1)和低的矫顽力Hc (20.81 Oe)。这种高饱和磁化强度、低矫顽力的磁性空心微球粒子可以应用在生物医药等领域。更多还原

【Abstract】 Because of low cost, low pollution, high resistance to corrosion and good stability, iron oxides are widely applied in many industry fields, such as catalysis, painting, magnetic recording medium, magnetic coating, gas sensor, and bioengineering etc. In spite of their numerous synthesis techniques with special advantages, the liquid-phase synthesis process still possesses some drawbacks. Up to now, for chemists and materials scientists, it still is an important challenge to explore new liquid-phase methods with the characterizes of simple equipment, easy operation, low cost, and high yield in order to facilely modulate the size and structure of the products. Therefore, in this paper, iron oxide nanomaterials with different morphologies was prepared by simple, low cost, and green liquid-phase methods, and the formation mechanism and novel physical/chemical properties of the as-made nanostructures are also studied.In the acidic environment,α-FeOOH/α-Fe2O3 nanostructures with different morphologies are obtained by controlling reaction temperature. The results showed that the morphologies of the products were highly dependent on the reaction temperature. among them, the nanorods were apt to form at the relatively high temperature, and the layered one-dimensional nanostructures are prone to obtain at the relatively low temperature. The layer oderedα-Fe2O3 nanostructures displayed higher BET surface area (129.16 m2/g) and better photocatalysis properties, where RhB can be effectively degradated into other small molecules after UV irradiation for 180min.Fe3O4 nanoparticles are obtained by an air oxidation method. The influences of experiment conditions, such as air flow rate, reaction temperature, reaction time, and alkali content etc. on the morphology and structure of Fe3O4 products were investigated in detail. It was found that the otahedral Fe3O4 nanoparticles were synthesised by using KNO3 as the oxidant.Magnetic hollow microspheres composed of small particles are synthesised by a solvothermal process, without addition of any reducing agent, surfactant, or template. Changing the content of alkali, sodium hypophosphites and the water can effectively tune the morphologies of magnetic hollow microspheres. Magnetic hollow microspheres obtained at 200℃exhibited higher saturation magnetization (80.17 emu·g-1) and lower coercivity (20.81 Oe) compared with those obtained at 160℃, due to the bigger paticle size, The magnetic hollow microspheres reported here can be applied in biological and medical fields.更多还原