Carbon Nanotubes: Synthesis via Chemical Vapour Deposition without Hydrogen, Surface Modification, and Application

The present study describes the growth of carbon nanotubes (CNTs) from liquefied petroleum gas (LPG) on an Fe2O3/Al2O3 precatalyst via a chemical vapour deposition (CVD) process without hydrogen. The obtained multiwalled CNTs exhibit a less-defective structure with an identical external diameter of tubes of around 50 nm. The growth mechanism of CNTs suggests that the Fe2O3/Al2O3 precatalyst is reduced to Fe/Al2O3 during the synthesis process using the products of LPG decomposition, and the tip-growth mechanism is suggested. The resulting CNTs are surface-modified with potassium permanganate in the acid medium and used as an adsorbent for copper from aqueous solutions. The Langmuir and Freundlich isotherm models are employed to evaluate the adsorption data, and the maximum adsorption capacity of Cu(II) is 163.7 mg·g−1.

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A study on synthesis of carbon nanotubes from liquefied petroleum gas by chemical vapour deposition

HUE UNIVERSITY JOURNAL OF SCIENCE NATURAL SCIENCE ◽

10.26459/hueuni-jns.v126i1b.3889 ◽

2017 ◽

Vol 126 (1B) ◽

pp. 135

Author(s):

Nguyen Duc Vu Quyen

Keyword(s):

Carbon Nanotubes ◽

Chemical Vapour Deposition ◽

Vapour Deposition ◽

Chemical Vapour ◽

Volume Ratio ◽

Bet Surface Area ◽

Synthesis Process ◽

External Diameter ◽

Liquefied Petroleum Gas ◽

Synthesis Of Carbon Nanotubes

In the present paper, the synthesis of carbon nanotubes from liquefied petroleum gas by chemical vapour deposition with the catalyst of Fe/SiO2 was showed. The morphology and tube diameter of carbon nanotubes depended on factors such as the flow of initial gases (H2 and LPG) and growth temperature that were investigated, repectively. The obtained CNTs was characterized by XRD, EDX, SEM, TEM and BET analyses. The results indicated that the synthesis process at 700oC for 2 hours with the volume ratio of H2:LPG = 1.75:1 (140 mL.min-1 of H2 and 80 mL.min-1 of LPG) was suitable for forming the material exhibitting nano-sized tubes. The multiwalled structure was obtained and the tubes were long and identical with external diameter of 52 nm and BET surface area of 93 m2.g-1.

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Towards the Large-Scale Synthesis of Carbon Nanotubes in Fluidised Beds

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2008.118 ◽

2008 ◽

Vol 8 (5) ◽

pp. 2450-2457 ◽

Cited By ~ 11

Author(s):

A. T. Harris ◽

C. H. See ◽

J. Liu ◽

O. Dunens ◽

K. Mackenzie

Keyword(s):

Carbon Nanotubes ◽

Chemical Vapour Deposition ◽

Large Scale ◽

Vapour Deposition ◽

Chemical Vapour ◽

Transition Metal Catalysts ◽

Synthesis Process ◽

Synthesis Methods ◽

Fluidised Bed ◽

Large Scale Synthesis

Carbon nanotubes (CNTs) are a form of crystalline carbon with extraordinary properties, making them valuable in a broad range of applications. However, the lack of suitable large-scale manufacturing techniques, which we define as being of the order 10000 tonnes per annum, continues to inhibit their widespread use. Of the three established synthesis methods for CNTs: (i) chemical vapour deposition (CVD), (ii) laser ablation, and (iii) arc discharge, CVD techniques show the greatest promise for economically viable, large-scale synthesis. In particular, the fluidised bed CVD (FBCVD) technique, where the CVD reaction occurs within a fluidised bed of catalyst particles, has the potential to produce high quality CNTs, inexpensively, in large quantities. In this work we report on the development of a catalytic chemical vapour deposition process, using batch fluidised bed reactors, for the synthesis of straight and spiral carbon nanotubes at pilot scale (up to 1 kg/hr). We believe this to be the first report of the synthesis of spiral carbon nanotubes using fluidised bed CCVD. Iron, nickel and cobalt transition metal catalysts supported on non-porous alumina substrates were fluidised in a mixture of nitrogen, hydrogen and ethylene at temperatures between 550 and 800 C for between 15 and 90 minutes. Nanotube yield was inferred from thermogravimetric analysis and the quality and size of the CNTs from transmission electron microscopy. Conflicting information in the literature about the influence of synthesis parameters on CNT properties suggests that further investigation is necessary to understand the synthesis process at a fundamental level, i.e., independent of reactor design and operation.

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Comparison of Straight and Helical Nanotube Production in a Swirled Fluid CVD Reactor

ISRN Nanotechnology ◽

10.5402/2012/985834 ◽

2012 ◽

Vol 2012 ◽

pp. 1-10

Author(s):

Graham Bathgate ◽

Sunny Iyuke ◽

Frank Kavishe

Keyword(s):

Carbon Nanotubes ◽

Chemical Vapour Deposition ◽

Vapour Deposition ◽

Continuous Production ◽

Chemical Vapour ◽

Single Walled Carbon Nanotubes ◽

Helical Structure ◽

Synthesis Process ◽

Helical Tubes ◽

Walled Carbon Nanotubes

Research into Carbon Nanotubes and their applications is fast becoming an extremely popular topic, and any means to greatly improve the synthesis process has a huge marketability. While investigating the feasibility of continuous production of single-walled carbon nanotubes in a vertical Swirled Fluid Chemical Vapour Deposition (CVD) reactor, it was discovered that helical nanotubes were lifted from the reactor by the gas current while straight tubes remained behind. Investigation into the merits provided by the helical structure illustrated the greatly increased likeliness for helical tubes to be lifted from the reactor by the carrier gas giving rise to positive speculation of their possible use in vertical CVD reactors in the future.

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