磁性金属氧化物超晶体的自组装与集合性能研究

Synthesis and functionalization of the uniform nanocrystals with tunable morphologies are of great significance for the research and applications of nanomaterials. Using these shape-controlled nanocrystals as building blocks to construct hierarchically self-assembled superlattices with some novel collective properties is one of the most exciting development trends of nanoscience and nanotechnology. In this program, we will develop a one-pot liquid-phase method for in-situ self-assembly of nano building blocks to construct magnetic metal oxide superlattices with uniform morphologies, highly-ordered structures and multifarious functions. Such self-assembly method is based on the dipole interactions of the nanoparticles in the solution and can be considered as a "green" synthetic route. By investigation the general assembly mechanism, the morphology, structure and scale of different superlattices can be easily controlled. This novel assembly strategy can provide new ideas for the large-scale preparations of superlattices. Moreover, exploring the collective properties of these assembled superlattices can extend the application fields of the magnetic metal oxides and can provide a solid basis for the design and exploitation of new type nano-based devices. The results of this program can greatly promoted the connection between the micro nanomaterials world and the macro device modules.

将纳米晶作为结构单元，组装成长程有序的高级结构，并发挥组装整体的新颖集合性能，是下一阶段纳米技术发展的一个重要方向目标。本项目主要针对目前国际上研究较少的磁性氧化物纳米组装体为研究体系，试图找到一种一步法实现纳米粒子制备及组装的"绿色"工艺，期待能够通过简单的溶剂热反应，通过调节纳米粒子间的偶极作用来实现颗粒的自组装，得到形貌可控，长程有序，功能丰富的纳米组装结构，为纳米组装体的大规模制备提供新的思路。通过揭示组装机制，构思调控组装体规模、结构和外形的方法，找到在液相环境中磁性金属氧化物纳米组装体原位自组装的通用性方法。探索组装体的集合性能，以拓宽磁性金属氧化物纳米组装体的应用领域，为纳米材料从微观向介观甚至宏观器件模块应用奠定良好的基础。

本项目主要研究了磁性金属氧化物超晶体的自组装与集合性能，开发了实现纳米粒子制备及原位自组装的“绿色”工艺，快速的、可控的构建了具有规则外形的、无衬底依赖的有序超晶体组装结构。在材料体系上，制备了不同形貌及微观结构的Co、Fe、Ni、V 等过渡金属单质/金属氧化物纳米颗粒，研究了自组装过程及催化、磁学性能；在单组分组装的基础上，研究掺杂型超晶体组装结构的制备方法，研究了掺杂元素的含量对材料形貌以及性能的影响，为材料功能的集成化奠定基础；在液相体系中探索了二元纳米粒子的复合组装，研究了异质组元的组装规律，为实现复合材料性能间的耦合奠定基础。另外，探索了不同氧化物纳米粒子的合成条件，如改变反应物配比，添加相关的表面活性剂等，调控了产物的形貌和尺寸，通过表征分析其组装结构，掌握了其组装规律，同时也研究相关产物的磁学、催化及电化学性能。结果表明，这些自组装的金属氧化物多级结构对高氯酸铵热分解具有非常优异的催化性能，在锂离子电池测试方面，也表现出了优异的电化学性能，如高的比容量、优异的循环稳定性和倍率性能。