石墨烯/磁性金属超薄片/石墨烯三明治式复合结构的制备及吸波性能研究

Due to the unique structure and novel properties of ultrathin two-dimensional (2D) materials, the research of ultrathin 2D materials has important theoretical significance and promising applications. However, the assembly of 2D materials and corresponding hybrid structures is still in its infancy. In this project, using organic amines as solvent and morphology control agent, ultrathin magnetic metal/alloys layer structures will be prepared using metal acetylacetonate (M(acac)2, M=Fe, Go, Ni, etc.) and other inorganic metal salts as metal precursors. Controllable chemical vapor deposition strategies will be developed to synthesize graphene/ultrathin magnetic metallic layer/graphene sandwich-like hybrid structures using ultrathin magnetic metal/alloys layers as templates and catalysts. The formation mechanism of the graphene/ultrathin magnetic metallic layer/graphene sandwich-like hybrid structures will be revealed based on the sophisticated analysis of the growth process and carefully characterization. The physicochemical properties, in particular, the electromagnetic properties and magnetic properties of these materials will be carefully investigated. The electromagnetic wave absorption properties of the hybrid structures will also be measured. A coherent picture will be drawn to show the clear relationship among their chemical composition, structures and properties. The main purpose of our study is to clarify related theory controlling mechanism of the graphene/ultrathin magnetic metallic layer/graphene hybrid structures and provide insight into the interaction of different structures and corresponding properties. The graphene/ultrathin magnetic metallic layer/graphene sandwich-like hybrid structures could not only integrate dielectric materials and magnetic material well in nanoscale and help to achieve impedance match conditions, but also have an opportunity to show some fascinating properties. It is predicted that great progresses both in synthetic strategies and property investigations will be achieved in the present project and finally provide guidance for the design of novel electromagnetic wave absorption materials with strong absorption property as well as lightweight and broad absorption frequency range.

超薄二维材料的研究具有重要的理论意义和诱人的应用前景，但基于二维材料的组装及复合体系的研究尚处于起步阶段。本项目拟发展可控的合成方法，以含铁、钴、镍等金属离子的盐类为金属源，以有机胺等为形貌控制剂，制备磁性金属及其合金的超薄片层结构，并以此为模板和催化剂，通过化学气相沉积法制备石墨烯/磁性金属超薄片/石墨烯三明治式复合结构。研究反应条件对反应过程和产物的影响，归纳总结相关复合结构的形成机制。探究石墨烯/磁性金属超薄片/石墨烯复合结构的物理化学性质，探讨相关材料在电磁波吸收等领域的应用。研究相关复合材料的化学组成、结构及其性能的内在关联。石墨烯/磁性金属超薄片/石墨烯三明治式复合结构可以在纳米尺度上实现磁性材料与介电材料的浑然一体，不仅能更好地满足阻抗匹配条件，还可能具有新颖的协同效应。因而，本项目研究有望在制备方法、性能研究等方面获得突破性进展，为开发轻质高效宽频段吸波材料提供新思路。

微波吸收材料在通信安全、电磁防护、军事隐身等领域应用广泛。由于其独特的二维结构和特殊的物理化学性质，石墨烯基材料被认为是微波吸收领域最有前途的材料。但单一石墨烯材料存在损耗机制受限和界面阻抗失配等问题，将石墨烯与磁性材料相结合是改善其阻抗匹配和提升微波吸收性能的最有效途径。因此本项目围绕着磁性金属/石墨烯复合结构等材料的合成与性能调控开展研究工作，在金属合金纳米结构、磁性金属/石墨烯复合结构等材料的可控制备及吸波性能研究方面取得可喜进展：1）通过CVD法制得FeCo@graphene核壳结构复合材料。数值模拟结果表明该复合材料对电磁场的磁损耗主要源于合金核，介电损耗源于石墨烯层，将石墨烯包覆厚度减小到单层将使电场和磁场达到更好的匹配，从而极大地增强了复合材料的微波吸收性能。这项研究不仅获得了性能优越、耐腐蚀能力强的吸波材料，还阐明了石墨烯/磁性金属复合材料的微波吸收增强机理，有助于指导高效微波吸收材料的设计和开发；2）构筑了三明治式Co3Fe7@C/RGO多组分复合材料，通过控制RGO与磁性颗粒的比例可以有效调节复合材料的复介电常数与阻抗匹配。优化产物呈现了优异的吸波性能，在模拟厚度为2.5 mm时，有效吸收频宽可达9.2 GHz。该研究为调整磁性金属/石墨烯复合材料的电磁参数和微波吸收特性提供了一种简便的策略；3）制备了Co3Fe7@C 蛋黄-壳结构复合物、由CoFe/C纳米片组装的中空棒状结构物等多种具有优异吸波性能的磁性颗粒/碳纳米结构复合材料，系统研究了相关材料的构效关系，可为设计新型超薄高效微波吸收材料提供了新的思路和方案；4）发展了一种限域氧化还原方法，制备了具有凹槽特征的铁钴镍三元合金双面神微粒；发现化学过程可以起到类似加热的作用，在远低于相应材料熔点的温度下引发晶态纳米材料的类液体行为；相关研究可能促进发展新的纳米功能材料的制备方法。.相关工作已经在Materials Today Nano、ACS Appl. Mater. Interfaces、Nanoscale等国际学术刊物上发表8篇基金标注论文，达成既定的研究目标。