Porous Fe3O4 nanoparticles: Synthesis and application in catalyzing epoxidation of styrene

A facile route was employed to synthesize porous magnetite via reaction of FeCl3.6H(2)O with N2H4 center dot H2O in ethylene glycol without any structure-directing agent. The resultant Fe3O4 particles were characterized by transmission electron microscopy, N-2 adsorption, X-ray photoelectron spectroscopy, and thermal gravimetric analysis. It was demonstrated that the particle size varied in the range of 40-220 nm, and the pore size of particles was centered around 2 nm. The gases produced in the formation process of the particles played key role in the formation of the porous structure. The obtained porous magnetite was used as support to immobilize Au nanoparticles with size less than 2 nm with the assistance of L-cysteine. The as-prepared Fe3O4 particles can effectively catalyze epoxidation of styrene, and the immobilization of Au nanoparticles on the Fe3O4 support significantly improved the activity of the catalyst. (C) 2011 Elsevier Inc. All rights reserved.