Fabrication of superparamagnetic macroporous Fe3O4 and its derivates using colloidal crystals as templates

In this paper, we reported the preparation of superparamagnetic macroporous Fe3O4 and its derivates using organic colloidal crystal as templates and their catalytic activity for chemical vapor deposition. The poly(styrene-methyl methacrylate-acrylic acid) (P(St-MMA-AA)) copolymer colloids were deposited in an orderly manner onto the silicon surface, together with the infiltration of the Fe3O4 nanoparticles into the interspaces of the colloids. The formed hybrid colloidal crystal subsequently was immersed in tetrahydrofuran to remove the organic components fully to obtain a macroporous Fe3O4 framework with three-dimensional porous structure. The macroporous Fe3O4 exhibits superparamagnetism due to the magnetic coupling of Fe3O4 nanoparticles in the structure. Macroporous Fe2O3 and Fe materials were obtained based on oxidization and reduction of the macroporous Fe3O4, respectively. It was demonstrated that the macroporous Fe3O4 materials possess catalytic activity and can induce growth of carbon nanotubes. (C) 2010 Elsevier Inc. All rights reserved.