CaCo3 supported Co-Fe catalysts for carbon nanotube synthesis in fluidized bed reactors
✍ Scribed by Chee Howe See; Andrew T. Harris
- Publisher
- American Institute of Chemical Engineers
- Year
- 2008
- Tongue
- English
- Weight
- 707 KB
- Volume
- 54
- Category
- Article
- ISSN
- 0001-1541
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✦ Synopsis
Abstract
The synthesis of carbon nanotubes (CNTs) on a cobalt‐iron (Co‐Fe) catalyst supported on a calcium carbonate (CaCO~3~) substrate, contained within a fluidized bed was investigated for the first time. CaCO~3~ supported catalysts, prepared using traditional wet impregnation techniques result in a soft and sticky powder requiring special arrangements to ensure satisfactory fluidization. A modified method developed using citric acid complex resulted in CaCO~3~ supported catalysts that can be classically fluidized without special arrangements. The issue of Fe^3+^ (aq) hydrolysis above its critical pH of ∼3.5 was also addressed. A carbon yield consistently greater than 10 times the weight of the catalyst metal loading was obtained. Thermogravimetric analysis coupled with mass spectrometry showed a single peak centered on 575°C, with no peaks below 400°C, indicating that an insignificant quantity of amorphous carbon was present. Transmission electron microscopy verified that the products contained a large proportion of CNTs. © 2008 American Institute of Chemical Engineers AIChE J 2008