Synthesis and magnetic properties of iron nanoparticles confined in highly ordered mesoporous carbons

摘要

The iron nanoparticles confined in highly ordered mesoporous carbons (OMCs) have been directly synthesized through a simple soft templating method by using resorcinol-formaldehyde (RF) as a carbon precursor, triblock copolymer Pluronic F127 as a template agent and hydrated iron nitrite as an iron source. This synthesis was carried out by the carbonization of the F127/[Fe(H_2O)_9] (NO_3)_3/RF composites self-assembled in an acidic medium, which was generated from the self-hydrolysis of precursory salt. The effects of iron loading contents on the morphology, pore feature and magnetic properties of the iron nanoparticles confined in OMCs were characterized by the X-ray diffraction, transmission electron microscopy, nitrogen sorption and vibrating-sample magnetometer measurement. It was found that Fe~(3+) was captured by the network of F127/RF and further reduced into metallic Fe nanoparticles during the carbonization. The results showed that the carbon material exhibited highly ordered mesoporous structure, and the iron nanoparticles were uniformly confined in the OMC walls when the Fe/R molar ratio was around 0.1. The saturation magnetization Ms, remanent magnetization Mr, and coercivity Hc of the Fe/OMC composites increased with the increasing of Fe/R molar ratio. The Fe/OMC composites exhibited the soft ferromagnetic behavior and the magnetization parameters could be adjusted by the content of iron.