Preparation of carbon-coated transition metal particles from mixtures of metal oxide and polyvinylchloride

Carbon-coated alpha-iron particles ca 100 mm in diameter were prepared through a simple heat-treatment of mixtures of Fe3O4 and polyvinylchloride (PVC) at 1000 degrees C in an Ar flow. After HCl treatment of the particles to remove iron and iron compounds, hollow carbon particles were seen under the scanning electron microscope. According to thermogravimetric analysis of the Fe3O4-PVC mixture, the formation of carbon-coated alpha-iron particles proceeds in four steps with weight loss, the first two steps being due to the pyrolysis and carbonization of PVC, and the last two to the reduction of Fe3O4 to alpha-Fe. Using the other transition metal oxides, NiO, CoO and Cu2O, carbon-coated respective metal particles were also prepared using the same procedure. (C) 1999 Elsevier Science Ltd. All rights reserved.