单分散Fe_3O_4亚微米球的粒径控制合成及表征

Size-controlled Synthesis and Characterization of Monodisperse Fe_3O_4 Submicrospheres

采用溶剂热还原法,以FeCl3.6H2O和乙二醇为原料,在200℃相对低温条件下成功合成四氧化三铁微米球。通过改变实验条件,可在115～435nm有效调控Fe3O4亚微米球的粒径。采用X射线衍射仪(XRD)、透射电子显微镜(TEM)和扫描电子显微镜(SEM)对样品的结构、粒径、形貌和组成进行了分析,并于室温测试了它的磁学性能。结果表明,产物Fe3O4亚微米球为反尖晶石结构,330nmFe3O4亚微米球的矫顽力(Hc)为6644.93A/m,饱和磁化强度(Ms)为81.2emu/g,剩余磁化强度(Mr)为14.6emu/g。研究了乙二醇和NaOH的浓度、反应时间对产物形貌的影响,结果表明,乙二醇在Fe3O4亚微米球的形成过程中起着关键作用,并提出了可能的生长机理。

Fe3O4 submicrospheres were synthesized by the solvothermal synthesis at 200 ℃,using FeCl3·6H2O and ethylene glycol as reactants.The size of as-prepared Fe3O4 submicrospheres could be controlled in the range of 115~435 nm in diameter by adjusting some growth parameters.The structure,size,morphology and composition of the as-prepared Fe3O4 submicrospheres were characterized by X-ray powder diffraction（XRD）,transmission electron microscopy（TEM）,scanning electron microscopy（SEM）.The results showed that the Fe3O4 submicrospheres were of inverse spinel structure.The magnetic propertie of 330 nm Fe3O4 submicrospheres has been detected by a vibrating sample magnetometer at room temperature.The coercive force,saturation magnetization and remanent magnetization of 330 nm Fe3O4 submicrospheres are about 6 644.93 A/m,81.2 emu/g and 14.6 emu/g,respectively.The influence of ethylene glycol,concentration of NaOH,and reaction time on the morphology development was experimentally investigated.It was found that the ethylene glycol molecules have a significant effect on the formation of Fe3O4 submicrospheres.A possible mechanism was also proposed to account for the growth of these Fe3O4 submicrospheres.