淀粉基碳包覆铁纳米胶囊的合成及其磁学性能

Preparation and magnetic properties of carbon encapsulated iron nanocapsules from starch

以淀粉为碳源,通过热解炭化铁/淀粉复合物,成功制备出碳包覆铁(Fe@C)纳米胶囊。在这一过程中淀粉有双重作用,既是碳源又是铁纳米颗粒的稳定剂。采用透射电镜、X射线衍射及振动样品磁强计研究了(Fe@C)纳米胶囊的结构和磁学性能。发现Fe@C纳米胶囊具有完美的铁核(bcc-Fe)/碳壳(石墨层片)包覆结构,其尺寸介于30nm^40nm之间;Fe@C纳米胶囊在室温下有低的剩磁比(Mr/Ms=0.11),表明它在室温下具有超顺磁性。

Carbon encapsulated iron （Fe@C） nanocapsules were successfully prepared by pyrolyzing iron/ starch composites under mild conditions, in which starch functioned as carbon precursor and stabilizer for iron nanoparticles. The as-obtained Fe@C nanocapsules were examined by TEM, XRD and a vibrating sample magnetometer. Results show that the Fe@C nanocapsules with diameters in a narrow range of 30-40 nm feature wellconstructed core/shell structures, consisting of a bcc-Fe core and a graphitic shell. The Fe@C nanocapsules have a low ratio of remanence to saturation magnetization （Mr/Ms = 0.11 ）, implying that they are superparamagnetic at room temperature.