Correlation between metal catalyst particle size and carbon nanotube growth

A series of Fe catalysts, with different mean diameters, supported on alumina with different molar ratios, was studied before and after carbon single walled nanotubes growth using magnetic measurements and Raman scattering techniques (laser excitation wavelengths from 1.17to2.54eV) to follow changes on catalyst particle size and composition, as well as the relationship between particle size and diameter of nanotubes grown. In all cases, an increase and redistribution of the particle size after the growth was concluded based on the blocking temperature values and Langevin function analysis. This is explained in terms of agglomeration of particles due to carbon-induced liquefaction accompanied with an increase in the catalyst mobility. For large particles no direct correlation between the catalyst size and the nanotube diameters was observed.

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“…Redistribution of Ni catalyst particle size supported on amorphous carbon film during carbon SWNT growth was also reported in Ref. 42.…”

Section: Laser Excitation ͑Nm͒supporting

confidence: 59%

Evolution of catalyst particle size during carbon single walled nanotube growth and its effect on the tube characteristics

Harutyunyan

Tokune

Mora

et al. 2006

Journal of Applied Physics

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“…37,38 From a 1 TPa value in the small tube diameter range it dropped to ∼10-50 GPa for wider tubes of 20-40 nm. This was attributed to the metastablecatalyst growth model and the lack of carbon supply needed for the growth of large diameter tubes 39,40 resulting in carbon nanotube walls with extended defects. This could be improved with the choice of more efficient catalytic systems and reaction kinetics as well as with post-growth treatments.…”

Section: Discussionmentioning

confidence: 99%

Reinforcement of CVD grown multi-walled carbon nanotubes by high temperature annealing

et al. 2013

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We report on the increase of the Young's modulus (E) of chemical vapor deposition (CVD) grown multi-walled carbon nanotubes (MWNTs) upon high temperature heat treatment. The post heat-treatment at 2200–2800ºC in a controlled atmosphere results in a considerable improvement of the microstructure, chemical stability and electro-physical properties of the nanotubes. The Young's modulus of MWNTs of different diameters was measured by the deflection of a single tube suspended across the hole of silicon nitride membrane and loaded by an atomic force microscope tip. Contrary to previous reports, a strong increase of E was feasible due to the improved growth conditions of pristine carbon nanotubes and to the improved heat treatment conditions. However, the elastic modulus of CVD grown MWNTs still shows strong diameter dependence resulting from the remaining structural inhomogeneities in large diameter nanotubes.

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“…One group is significantly longer and wider than the other, with diameters approximately the same as the Ni droplet size that was on the processed film, as has been observed elsewhere. 14 The Ni droplets can be observed at the end of these tubes, as black dots in the SEM image. The CNTs in the second set appear as an ''undergrowth'' and are much shorter with smaller diameters than the first set.…”

mentioning

confidence: 97%

“…[9][10][11][12][13] Many different techniques are used for the preparation of suitable substrates. 12,14,15 To date the formation of suitable catalyst substrates for CNT growth is accomplished by thermal annealing of thin films deposited by magnetron sputtering 12 or thermal evaporation. 13 The latter study involving nanostructuring of Ni on oxide films at temperatures below 500°C.…”

mentioning

confidence: 99%

Excimer laser nanostructuring of nickel thin films for the catalytic growth of carbon nanotubes

Henley

Poa

Adikaari

et al. 2004

Applied Physics Letters

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Pulse laser ablation and subsequent laser nanostructuring at room temperature has been employed to produce nanostructured Ni on SiO 2 /Si substrates for catalytic growth of carbon nanotubes. The resultant nanostructured surface is seen to consist of nanometer sized hemispherical droplets whose mean diameter is controlled by the initial metal thickness, which in turn is readily controlled by the number of laser pulses. Vertically aligned multiwall carbon nanotube mats were then grown using conventional plasma enhanced chemical vapor deposition. We show that within a single processing technique it is possible to produce the initial metal-on-oxide thin film to a chosen thickness but also to be able to alter the morphology of the film to desired specifications at low macroscopic temperatures using the laser parameters. The influence of the underlying oxide is also explored to explain the mechanism of nanostructuring of the Ni catalyst.

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Correlation between metal catalyst particle size and carbon nanotube growth

Cited by 214 publications

References 14 publications

Evolution of catalyst particle size during carbon single walled nanotube growth and its effect on the tube characteristics

Evolution of catalyst particle size during carbon single walled nanotube growth and its effect on the tube characteristics

Reinforcement of CVD grown multi-walled carbon nanotubes by high temperature annealing

Excimer laser nanostructuring of nickel thin films for the catalytic growth of carbon nanotubes

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