石墨包覆铁纳米粒子的结构及生长机制

Microstructure and Its Growth Mechanism of Graphite Encapsulated Iron Nanoparticles

用金属钾还原2阶FeCl_3石墨层间化合物(FeCl_3-GICs)前驱体制备了石墨包覆纳米α-Fe。X射线衍射(XRD)、X射线能量色散谱(EDX)分析表明所制备样品由石墨、α-Fe和少量KCl组成,透射电镜(TEM)观察发现样品中的α-Fe为纳米粒子,嵌入在石墨结构层间,含量丰富。高分辨透射电镜(HRTEM)观察证实α-Fe纳米粒子由多晶组成,呈二维或准二维形态,α-Fe纳米晶的空间取向严格受石墨结构层控制。在实验基础上提出了一种石墨包覆纳米α-Fe的可能生长机制。

Carbon encapsulated magnetic nanometals are considered to have many potential applications. In this present work, the graphite encapsulated α-Fe nano particles are prepared by reduction of stage-2 graphite intercalation compounds （GICs） of FeCl3 with metallic potassium. The X-ray diffraction analysis （XRD） and energy dispersive X-ray spectroscopy （EDX） indicate that the synthesized sample consists of graphite, α-Fe and a little of KCl. The transmission electron microscopy （TEM） observation shows that there are abundant α-Fe nanoparticles encapsulated in the graphite. The high-resolution TEM （HRTEM） observation reveals that the nanoparticles of α-Fe consist of polycrystals or twins,which are real or quasi two-dimension in shape, and whose space orientation is strictly controlled by the graphite. Based on the experiment results, a possible growth model of the graphite encapsulated α-Fe nanoparticles is proposed.