Formation of bamboo-shaped carbon filaments and dependence of their morphology on catalyst composition and reaction conditions

Carbon filaments and nanometric carbon particles formed from methane on nan o-sized Ni-Cu/Al2O3 catalyst at 720-830 degreesC were investigated with a t ransmission electron microscope. Bamboo-shaped carbon filaments were found formed at moderate temperatures. Their morphology depends on the amount of copper doped into the catalyst, the composition of the feed gas and the rea ction temperature. Under appropriate conditions, a morphologically pure bam boo-shaped carbon filament can be produced. It is likely that the formation of the quasi-liquid state of the metal nanoparticles during the growth of the carbon is critical for the formation of bamboo shape. The sensitivity o f the carbon morphologies to the nano-carbon to the characteristics of cata lyst and reaction conditions provides some room for the nanosize constructi on with carbon under moderate catalytic conditions. (C) 2001 Elsevier Scien ce Ltd. All rights reserved.