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The role of molybdenum in Fe–Mo–Al2O3 catalyst for synthesis of multiwalled carbon nanotubes from butadiene-1,3

Paper ID Volume ID Publish Year Pages File Format Full-Text
42311 45920 2009 7 PDF Available
Title
The role of molybdenum in Fe–Mo–Al2O3 catalyst for synthesis of multiwalled carbon nanotubes from butadiene-1,3
Abstract

MoO3–Fe2O3–Al2O3 catalysts were prepared by co-precipitation of mixed hydroxides from soluble salts. It was found that the 55%Fe2O3–Al2O3 aluminum–iron catalyst calcined in air at 500–700 °C consisted of a solid solution based on hematite where a part of iron atoms was substituted for aluminum. The modification of the aluminum–iron catalyst with molybdenum results in the formation of a solid solution based on hematite where a part of iron atoms is substituted for aluminum and molybdenum ions. At 700 °C the MoO3–Fe2O3–Al2O3 catalysts are reduced under the action of the feed. The dependence of the multiwalled carbon nanotube (MWNT) yield over MoO3–Fe2O3–Al2O3 catalysts on the molybdenum concentration has a maximum. Small concentrations of MoO3 (up to 6.5 wt.%) added to the aluminum–iron catalyst increase the dispersity of the active metal particles and alter their properties due to the formation of a Fe–Mo alloy. Its formation leads to the decrease of the nanotube growth rate and makes the catalyst more stable. The overall yield of the carbon nanotubes increases. Further increase of the molybdenum concentration leads to the decrease of the nanotube yield because the catalytically active Fe–Mo particles are enriched too much with molybdenum. In addition, excess molybdenum forms molybdenum carbide α-Mo2C, in which part of the molybdenum atoms are substituted for iron atoms, and which is inactive in the MWNT growth.

Graphical abstractA maximum has been observed on the dependence of the carbon nanotube yield over MoO3–Fe2O3–Al2O3 catalysts on the molybdenum concentration. Small concentrations of molybdenum (up to 5.2 wt.%) added to the aluminum–iron catalyst increase the dispersity of the metal particles, makes the catalyst more stable and increases the overall yield of the carbon nanotubes.Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Molybdenum; Iron oxide; Catalyst; Carbon nanotubes; Butadiene-1,3
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The role of molybdenum in Fe–Mo–Al2O3 catalyst for synthesis of multiwalled carbon nanotubes from butadiene-1,3
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 363, Issues 1–2, 1 July 2009, Pages 86–92
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us