One-step Synthesis of highly ordered mesoporous Fe/carbon composites using soft templating routes

Ordered mesoporous PFR-Fe/C composites have been synthesized via a ‘‘one-pot’’ assembly strategy associated with a direct carbonization process by using phenolic resol (PR) as a carbon source, inorganic salt hydrated iron nitrite as an iron source and amphiphilic triblock copolymer Pluronic F127 as a template. The main strategy of this approach is to use the iron precursors as the coordinationcenter with phenol. The obtained mesoporous Fe/Fe ₂ O ₃ /carbon composites (PFR/C-Fe) exhibit uniform pore sizes about 6.78 nm, high specific surface areas about 572 m ² g ^-1 , and high pore volumes 0.70 cm ³ g ^-1 . With this facile ‘‘one-pot’’ assembly approach, one can incorporate as high as about 30 wt % of iron in the composites. The resultant materials were characterized using nitrogen sorption, X-ray diffraction, and transmission electron microscopy. It was found that the final products with a highly ordered mesostructure were obtained when the Fe/R ratio was around 1:6. Especially, the increased iron content induces the enlarged particle sizes of the iron nanocrystals, together with a high dispersion in the amorphous carbon framework, but the ordering decreased. Iron species in the mesoporous carbon matrix existed in two states, metallic Fe and α-Fe ₂ O ₃ . Metallic Fe nanoparticles are dominantly buried in the walls of the mesoporous carbon while α-Fe ₂ O ₃ nanoparticles are mostly located on the surface. When the iron particles have sizes larger than the mesopore wall thickness, they can extend from the carbon walls into mesopore channels, and hence bring a rougher pore surface and a lower degree of mesostructure regularity. These mesoporous Fe/Fe ₂ O ₃ /carbon composites materials composites with high surface area, large pore size and super paramagnetic property show excellent adsorption properties for bulky dye fuchsin base. The excellent magnetic materials makes it useful in magnetic separation.