Influence of ferrocene addition on the morphology and structure of carbon from petroleum residue

Nano-sized iron particle/carbon composites have been synthesized from a petroleum residue by heating at 420 degreesC with ferrocene under pressure. The morphologies and structural features of the composites were investigated using TEM, HREM and XRD measurements. The effect of ferrocene addition on the development of turbostratic carbon from the petroleum residue was discussed. It was found that, by increasing the amount of ferrocene added from 3% to 20%, the size of the nano-iron particles tended to increase from 20-80 nm to 30-180 nm. The iron particles pyrolyzed from ferrocene mainly exist in the forms Fe-O and Fe1-xS when the ferrocene content was low (3% and 6%), and alpha-Fe when ferrocene contents were high (10% and 20%). Upon further heat treatment in the range 500 to 900 degreesC, the iron particles tended to aggregate and Fe-O and Fe1-xS were transformed into alpha-Fe and austenite. In comparison with the carbon formed without ferrocene addition, the resulting carbon exhibited a turbostratic structure as shown by HREM, in which the d(002) spacing decreased with the increase of ferrocene loading and increasing temperature, suggesting the carbonization was promoted by the catalysis of the nano-iron particles. (C) 2003 Elsevier Ltd. All rights reserved.