复合氧化铁微纳结构的可控组装及性能研究

The performance of nano materials depend on their composition and particle sizes and shapes as well as the morphologies and microstructures of their assembly. In this project, α-Fe2O3/Fe3O4 nanocrystals with well-defined shapes and uniform sizes will be prepared, which further serve as building blocks for the multi-scale self-assembly of hierarchical structures directed by the weak interaction between the constructing units and the structure directing agent molecules. New strategy for the preparation of α-Fe2O3/Fe3O4 hierarchical nano-assemblies with controllable magnetic properties will be developed. The mechanisms for the nucleation, growth, and self-assembly of the α-Fe2O3/Fe3O4 hierarchical structures will be investigated. The influence of various parameters on their structures and their properties of the nanoassemblies will be investigated, such as the size, anisotropic shape, surface properties, crystallinity, and assembly method of the primary nano-units, as well as the compositions and interface properties of the complex assemblies. It is expected that this kind of composite structures can acquire the properties of Fe2O3 and Fe3O4 species, and some new magnetic properties resulting from the exchange coupling interaction of the assembled α-Fe2O3/Fe3O4 nano building blocks. Scientific evidence will be provided to discuss the exchange coupling mechanism of the composite iron oxide hierarchical structures and explore the science problem in them.

纳米材料的性能不仅与其组成和颗粒尺寸有关，还与颗粒形状及其聚集体的形貌、结构有关。本项目旨在对α-Fe2O3、Fe3O4等氧化铁纳米构建单元的形状各向异性进行调控，并利用所得特定形状的纳米构建单元与结构导向剂分子间弱的相互作用进行多尺度分级有序组装，发展制备结构可控的各向异性分级结构α-Fe2O3/Fe3O4复合氧化铁有序组装体的新技术，探索纳米复合组装体的成核与生长机制以及分级微结构的有序组装机制。研究初级纳米构建单元的尺寸、各向异性形状、表面性质、结晶状态、复合组装方式以及组装体的组成、各向异性与界面结构等对其微结构和性能的影响规律。使该结构兼有α-Fe2O3与Fe3O4各自的性能，并赋予它们由纳米构建单元的磁交换耦合所产生的新的纳米共轭效应，为揭示复合氧化铁有序组装体纳米磁交换耦合微观作用机制、阐明分级结构磁-磁纳米各向异性复合组装结构中的基本科学问题提供科学依据。

纳米材料的性能不仅与其组成和颗粒尺寸有关，还与颗粒形状及其聚集体的形貌、结构有关。通过本项目研究, 对α-Fe2O3、Fe3O4、FeOOH等氧化铁纳米构建单元的形状各向异性进行调控，并利用纳米构建单元与结构导向剂分子间弱的相互作用进行多尺度分级有序组装，发展了制备结构可控分级结构氧化铁以及复合氧化铁有序组装体的新技术，探索了纳米组装体的成核与生长机制以及分级微结构的有序组装机制。建立了高矫顽力α-Fe2O3介晶空心微球的液相反应制备方法，明确了了α-Fe2O3纳米棒有序组装体的结构、形状与磁性能的调控机制，类方块状空心球的矫顽力高达7800Oe。提出了NiSO4调控制备FeOOH多级结构及相转变制备镍掺杂Fe2O3多级结构微球的新路线。提出表面氧化诱导的Kirkendall效应，制备了Fe3O4/Fe2O3复合空心球。以α-Fe2O3或Fe3O4初级纳米组装体为母体进一步组装异质双组份、多组分的多重纳米结构，建立了氧化铁复合多重纳米结构新型功能材料的制备方法。对系列组装体新的磁学性能及其影响因素进行了探索。在本项目的支持下，已发表SCI论文1篇，申请并公开国家发明专利4件。另有根据本项目成果整理待发表研究论文3篇。