【作者】 毛宝东；

【导师】 王恩波；

【作者基本信息】 东北师范大学 ， 无机化学， 2007， 硕士

【摘要】 由于纳米结构磁性材料广泛的潜在应用,最近大量的研究集中于此领域以期控制其组成、微结构和形貌,而各种铁氧化物则代表了在为常见和重要的磁性材料。探索和发展合成铁氧化物纳米材料的简单方法,特别是基于水溶液的方法,对于纳米结构磁性材料的简单廉价合成及其进一步的大批量应用都有重要的意义。在本文中,利用合成体系的内在化学性质,通过选择底物、控制晶粒成核和生长以及调节反应环境,发展了水溶液合成铁氧化物纳米材料的的简单的方法,以期开辟简单、廉价的合成磁性铁氧化物纳米材料的新路。1、通过在水热条件下浓碱处理铁粉,成功的制备了直径~500nm的均匀的高质量的四氧化三铁八面体粒子。2、通过水热条件下多酸辅助的水解方法成功的制得了均匀的氧化铁中空球。所得到的中空球直径600~700 nm,呈现高的比表面积和反常的与其微结构相关的弱铁磁性行为。中空球的形成过程可被归结为一个多酸辅助的水解沉积-溶解过程。3、将多酸辅助水解方法进一步发展用于制备直径10-20 nm的β–FeOOH多孔纳米棒。所制得的β–FeOOH多孔纳米棒直接在空气中煅烧即可得到多孔氧化铁纳米棒。4、通过水热处理葡萄糖、Fe3+和M2+的混合溶液和随后的煅烧处理,成功的制备了一系列均匀的铁氧体MFe2O4 (M=Mg, Co, Ni, Zn)中空微球。中空球的形成来自于原位形成的碳核作为模板。其壳厚度、结晶度和磁性可通过改变实验参数来很好的调控。更多还原

【Abstract】 Recently considerable research interest is focused on nanostructured magnetic materials, with the expectation to control their composition, microstructure and morphology due to their wide potential uses. Various iron oxide based materials are still the most important and common magnetic materials. Hence, developing simple process for the preparation of various iron oxides, especially aqueous solution strategy, is of great interest for the simple and low cost synthesis of magnetic materials for their further large-scale applications.In the present work, through exploring the inherent chemical properties of the synthetic systems, several aqueous solution processes are developed for morphology controlled fabrication of iron oxides via substrate selection, nucleation and growth control and changing reaction environment, towards developing new strategies for simple and low cost synthesis of magnetic materials.1. High quality Fe3O4 octahedral particles of ~500nm were successfully synthesized from iron powders by simple hydrothermal treatment with 10 M NaOH at 180°C.2. Uniform hollow hematite spheres were successfully synthesized by a simple polyoxometalate-assisted hydrolysis process of Fe3+ solution under hydrothermal condition. The hollow spheres with diameters of 600-700 nm show a high surface area and weak ferromagnetic behavior due to their porous structure. Formation of the hollow hematite spheres may be attributed to a polyoxometalte-assisted forced hydrolysis and dissolution process.3. Uniform porous p-FeOOH nanorods of 10-20 nm have been sucessfully fabricated by further exploring the polyoxometalate-assisted hydrolysis process of Fe3+ solution. Porous hematite nanorods could be obtained from direct calcination of the P-FeOOH nanorods.4. Uniform ferrite MFe2O4 (M=Mg, Co, Ni, Zn) hollow spheres are successfully prepared by hydrothermal treatment of a mixed solution of glucose, Fe3+ and M2+ and a following calcination process. Formation of the hollow spheres is ascribed to the in situ formed carbon core as template. The shell thickness, crystallinity and consequently magnetic property of the ferrite hollow spheres could be tuned by varying the synthetic parameters.更多还原