Facile preparation of carbon coated magnetic Fe3O4 particles by a combined reduction/CVD process

In this work, we report a simple method for the preparation of magnetic carbon coated Fe₃O₄ particles by a single step combined reduction of Fe₂O₃ together with a Chemical Vapor Deposition process using methane. The temperature programmed reaction monitored by Mössbauer, X-ray Diffraction and Raman analyses showed that Fe₂O₃ is directly reduced by methane at temperatures between 600 and 900 °C to produce mainly Fe₃O₄ particles coated with up to 4 wt% of amorphous carbon. These magnetic materials can be separated into two fractions by simple dispersion in water, i.e., a settled material composed of large magnetic particles and a suspended material composed of nanoparticles with an average size of 100-200 nm as revealed by Scanning Electron Microscopy and High-resolution Transmission Electron Microscopy. Different uses for these materials, e.g., adsorbents, catalyst supports, rapid coagulation systems, are proposed.