Present work concerns iron-catalyzed growth of multi-walled C nanotubes (MWCNTs) by decomposition of isobutane (C(4)H(10)). MWCNTs are prepared, by chemical vapor deposition (CVD) at 600 degrees C, in C(4)H(10)-H(2)-He atmosphere over 29 wt.%Fe/Al(2)O(3) catalysts. After purification, reaction products are analyzed by scanning electron microscopy (SEM), Raman spectroscopy (RS) and thermo-gravimetric analysis (TGA). The influence of the gas-mixture composition on the reaction issue is investigated by considering different gas-flowing setups: H(2) or C(4)H(10) flow is varied in the range 15-90 cc/min while keeping hydrocarbon or H(2) constant. The total flow is kept at 120 cc/min by using He as a balance-gas. Owing to these changes, diverse selectivity towards nanotubes, morphologies, size distributions, purity degrees and crystallinity are obtained, as evidenced by the characterization results.
Influence of gas mixture composition on yield, purity and morphology of carbon nanotubes grown by catalytic isobutane decomposition
GALVAGNO, Signorino;MILONE, Candida;PIPEROPOULOS, Elpida;PISTONE, Alessandro;
2009-01-01
Abstract
Present work concerns iron-catalyzed growth of multi-walled C nanotubes (MWCNTs) by decomposition of isobutane (C(4)H(10)). MWCNTs are prepared, by chemical vapor deposition (CVD) at 600 degrees C, in C(4)H(10)-H(2)-He atmosphere over 29 wt.%Fe/Al(2)O(3) catalysts. After purification, reaction products are analyzed by scanning electron microscopy (SEM), Raman spectroscopy (RS) and thermo-gravimetric analysis (TGA). The influence of the gas-mixture composition on the reaction issue is investigated by considering different gas-flowing setups: H(2) or C(4)H(10) flow is varied in the range 15-90 cc/min while keeping hydrocarbon or H(2) constant. The total flow is kept at 120 cc/min by using He as a balance-gas. Owing to these changes, diverse selectivity towards nanotubes, morphologies, size distributions, purity degrees and crystallinity are obtained, as evidenced by the characterization results.Pubblicazioni consigliate
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