Synthesis of carbon nanotubes with and without catalyst particles
© Rümmeli et al; licensee Springer. 2011
Received: 14 October 2010
Accepted: 7 April 2011
Published: 7 April 2011
The initial development of carbon nanotube synthesis revolved heavily around the use of 3d valence transition metals such as Fe, Ni, and Co. More recently, noble metals (e.g. Au) and poor metals (e.g. In, Pb) have been shown to also yield carbon nanotubes. In addition, various ceramics and semiconductors can serve as catalytic particles suitable for tube formation and in some cases hybrid metal/metal oxide systems are possible. All-carbon systems for carbon nanotube growth without any catalytic particles have also been demonstrated. These different growth systems are briefly examined in this article and serve to highlight the breadth of avenues available for carbon nanotube synthesis.
Metal catalyst particles
Ceramic and semiconductor catalysts
The controlled oxidation process depletes Si at the surface, enabling the construction of CNTs. However, the formation of the initial caps at the nucleation stage has yet to be clarified . Some argue a transformation process of surface graphene layers [20, 21] or amorphous carbon  forms nucleation caps. Others argue the formation of convex structures on the surface enable initial cap formation [23–25]. Single-walled carbon nanotubes (SWNTs) can also be grown from SiC nanoparticles in CVD as was shown by Takagi . Botti et al. [27, 28] demonstrated laser annealing of SiC nanoparticles as a technique to obtain CNT.
The potential of semiconducting catalyst particles was first demonstrated by Uchino et al. [29, 30] in which carbon-doped SiGe islands on Si were used to grow CNT after chemical oxidation and annealing treatments. Growth of the CNT was argued to occur from Ge clusters.
This is due to the greater thermodynamic tendency of Si to be oxidized as compared to Ge. Thus, the oxidation treatment results in the formation of SiO2 and the segregation of Ge clusters. Takagi et al.  also showed that SWNT could be grown directly from Ge particles as well as from Si nanoparticles.
In 2009, two groups showed SWNT formation using SiO2 nanoparticles [35, 36]. A little later Bachmatiuk et al. [37, 38] showed stacked cup CNT could be grown from amorphous SiO2 nano-particles. However, transmission electron microscopy (TEM), infrared (IR) and Raman spectroscopic studies showed the nano-particles at the root of the CNT to be SiC. Their data points to the carbo-thermal reduction of SiO2. This result is in contrast to X-ray photoemission studies (XPS) by Huang et al.  which did not show any carbide formation and hence they argued growth occurred from the SiO2 particles. Steiner et al.  also conducted XPS studies and also found no evidence for carbide formation when using zirconia as the catalyst. However, it should be noted that Bachmatiuk et al.  also found no carbide formation when using XPS despite other techniques clearly demonstrating the presence of carbides. This suggests XPS, which is a surface sensitive technique, may not be best suited to determine if oxides used as catalysts for CNT growth reduce to carbides or not during synthesis. Various other oxides, outside of those mentioned, including TiO2 and lanthanide oxides can also be used to grow carbon nanotubes . Templated CNT grown in porous alumina without catalyst particles have also been demonstrated . Further studies are required to better understand which oxide systems are stable and which are reducible. Previous studies of ours in which nano-crystalline oxides were subjected CVD reactions showed many oxides are stable, whilst others are not. These studies confirmed oxides are capable of graphitising carbon .
Hybrid metal/metal-oxide catalyst systems
Many of the oxides described above as catalytic nano-particles for CNT growth are often used as supports in supported catalyst CVD. Commonly used oxide supports are Al2O3, SiO2, TiO2 and MgO. All these oxides have been shown to grow CNT. Their role is primarily to stabilize the metal catalysts, viz. prevent coalescence. However, in oxide-supported metal catalysis it is well known that small clusters can have enhanced catalytic activity. A well-known example is Au, which is a bulk material is rather inert, but finely dispersed and deposited on oxides as small nano-clusters Au exhibits high catalytic ability (e.g. Haruta). This enhanced catalytic activity is generally accepted to occur at the circumference of the nano-cluster/support interface.
Another hybrid metal/metal-oxide example is the hydrocarbon dissociation over supported less active metal catalysts like Au and Cu, where it is argued that electron donation to the support creates d-vacancies for hydrocarbon dissociation .
All carbon systems
In short, there appear to be a variety of growth modes and investigating each is complicated. Ex situ studies by definition means the catalysts have had time to relax and re-crystallize before being subjected to any investigative method. Hence, ex situ studies are necessarily limited in that they cannot unequivocally testify to circumstances during growth. On the back of this some argue in situ measurements as the only way forward. However, these routes present key limitations such as the need to work at very low pressures, well beyond any conventional or commercial route would use, as is the case for TEM and XPS in situ studies. Moreover, in in situ TEM only tiny sample sizes are examined and in the case of XPS in situ examinations, as already discussed above, the technique is surface sensitive and hence provides limited information on the catalyst during growth. Another area to investigate is how nature produces carbon nanotubes. Surprisingly, there is little evidence on planet Earth for their formation with only a few examples of MWNT and none for SWNT . However, CNT may form more readily in outer space. Graphite whiskers have been found in high-temperature components of meteorites . In addition, it has been proposed they can form in protostellar nebulae via Fischer-Tropsch-type catalytic reactions [61, 62]. Recent experiments by the same group investigating the potential of Fischer-Tropsch and Haber-Bosch type reactions appear to support this hypothesis . Thus, it is the collective data from both ex situ and in situ examinations that are important; however, the limitations of each implemented technique, and the specifics of the synthesis route in question must be considered as there is no single universal growth mode.
There remains a fair amount of controversy in explaining carbon nanotube growth; this in part is due to the sheer number of possible synthesis routes and the fact that there is no single universal growth mode. Even so, tremendous advances have been made. This includes the development of new catalyst systems and even catalyst-free systems. Nonetheless the successful integration of CNT into applications and large-scale production processes remains limited and is dependant on the understanding of several fundamental issues. Some of these issues are highlighted by the disparate catalyst and catalyst free options available which raise new questions on nucleation and growth as well as the role of supports in supported catalysts. In some sense the rapid development of graphene may render CNT less important, for example, in the integration of carbon nanotubes in integrated circuit manufacturing, however, many of the questions raised in understanding carbon nanotube growth are directly relevant to graphene also.
chemical vapour deposition
free radical condensate
multi-walled carbon nanotubes
single-walled carbon nanotubes
transmission electron microscopy
X-ray photoemission studies.
MHR thanks the EU (ECEMP) and the Freistaat Sachsen, AB and FS the Alexander von Humboldt Foundation and the BMBF, FB the DFG (RU 1540/8-1), II the DAAD (A/07/80841) and CC the EU (CARBIO, Contract MRTN-CT-2006-035616). GC acknowledges support from the South Korean Ministry of Education, Science, and Technology Program, Project WCU ITCE No. R31-2008-000-10100-0.
- Iijima S: Helical microtubules of graphitic carbon. Nature 1991, 354: 56. 10.1038/354056a0View Article
- Krätschmer W, Lamb LD, Fostiropoulos F, Huffman D: Solid C 60 : a new form of carbon. Nature 1990, 347: 354.View Article
- Kroto HW, Heath JR, O'Brien SC, Curl RF, Smalley RE: C 60 : Buckminsterfullerene. Nature 1985, 318: 162. 10.1038/318162a0View Article
- Iijima S, Ichihaschi T: Single-shell carbon nanotubes of 1-nm diameter. Nature 1993, 363: 603. 10.1038/363603a0View Article
- Bethune DS, Kaing CH, de Vries MS, Gorman G, Savoy R, Vazquez J, Beyers R: Cobalt-catalysed growth of carbon nanotubes with single-atomic-layer walls. Nature 1993, 363: 605. 10.1038/363605a0View Article
- Hughes TV, Chambers CR: Manufacture of Carbon Filaments. US Patent 405480 (1889)
- Takagi D, Homma Y, Hibino H, Suzuki S, Kobayashi Y: Single-Walled Carbon Nanotube Growth from Highly Activated Metal Nanoparticles. Nano Lett 2006, 6: 2642. 10.1021/nl061797gView Article
- Takagi D, Kobayashi Y, Hibino H, Suzuki S, Homma Y: Mechanism of Gold-Catalyzed Carbon Material Growth. Nano Lett 2008, 8: 832. 10.1021/nl0728930View Article
- Rümmeli MH, Grüneis A, Löffler M, Jost M, Schönfelder R, Kramberger C, Grimm D, Gemming T, Barreiro A, Borowiak-Palen E, Kalbac M, Ayala P, Hübers H-W, Büchner B, Pichler T: Novel catalysts for low temperature synthesis of single wall carbon nanotubes. Phys Stat Sol B 2006, 243: 3101.View Article
- Borowiak-Palen E, Steplewska A, Rümmeli MH: On the use of Cu catalysts for tailoring carbon nanostructures in alcohol-CVD. Phys Stat Sol B 2009, 246: 2448. 10.1002/pssb.200982263View Article
- Rümmeli MH, Borowiak-Palen E, Gemming T, Pichler T, Knupfer M, Kalbac M, Dunsch L, Jost O, Silva SRP, Pompe W, Büchner B: Novel Catalysts, Room Temperature, and the Importance of Oxygen for the Synthesis of Single-Walled Carbon Nanotubes. Nano Lett 2005, 5(7):1209.View Article
- Bachmatiuk A, Schäffel F, Placha D, Martynkova GS, Ioannides N, Gemming T, Pichler T, Kalenczuk RJ, Borowiak-Palen E, Rümmeli MH: Tuning carbon nanotubes through poor metal addition to iron catalysts in CVD. Fuller Nanotubes Carbon Nanostruct 2010, 18: 703.
- Baker T: Formation of filamentous carbon. Chem Ind (London) 1982, 18: 698.
- Wagner RS, Ellis WC: Vapor-liquid-solid mechanism of single crystal growth. Appl Phys Lett 1964, 4: 89. 10.1063/1.1753975View Article
- Hofmann S, Csányi G, Ferrari AC, Payne MC, Robertson J: Surface Diffusion: The Low Activation Energy Path for Nanotube Growth. Phys Rev Lett 2005, 95: 036101. 10.1103/PhysRevLett.95.036101View Article
- Zhou W, Han Z, Wang J, Zhang Y, Jin Z, Sun Z, Zhang Y, Yan C, Li Y: Copper Catalyzing Growth of Single-Walled Carbon Nanotubes on Substrates. Nano Lett 2006, 6: 2987. 10.1021/nl061871vView Article
- Lu C, Liu J: Controlling the Diameter of Carbon Nanotubes in Chemical Vapor Deposition Method by Carbon Feeding. J Phys Chem B 2006, 110: 20254. 10.1021/jp0632283View Article
- Kusunoki M, Rokkaku M, Suzuki T: Epitaxial carbon nanotube film self-organized by sublimation decomposition of silicon carbide. Appl Phys Lett 1997, 71: 2620. 10.1063/1.120158View Article
- Kusonoki M, Suzuki T, Honjo C, Usami H, Kato H: Closed-packed and well-aligned carbon nanotube films on SiC. J Phys D 40: 6278. 10.1088/0022-3727/40/20/S12
- Kusunoki M, Suzuki T, Kaneko K, Ito M: Formation of self-aligned carbon nanotube films by surface decomposition of silicon carbide. Philos Mag Lett 1999, 79: 153. 10.1080/095008399177381View Article
- Watanabe H, Hisada Y, Murainakano S, Tanaka N: In situ observation of the initial growth process of carbon nanotubes by time-resolved high resolution transmission electron microscopy. J Microsc 2001, 203: 40. 10.1046/j.1365-2818.2001.00902.xView Article
- Kusunoki M, Suzuki T, Hirayama T, Shibata N: A formation mechanism of carbon nanotube films on SiC(0001). Appl Phys Lett 2000, 77: 531. 10.1063/1.127034View Article
- Konishi H, Matsuoka H, Toyama N, Naitoh M, Nishigaki S, Kusunoki M: Growth control of carbon nanotubes on silicon carbide surfaces using the laser irradiation effect. Thin Solid Films 2004, 464: 295. 10.1016/j.tsf.2004.06.002View Article
- Hayashi K, Mizuno S, Tanaka S, Toyoda H, Tochihara H, Suemune I: Nucleation Stages of Carbon Nanotubes on SiC(0001) by Surface Decomposition. Jpn J Appl Phys 2005, 44: L803. 10.1143/JJAP.44.L803View Article
- Maruyama T, Bang H, Kawamura Y, Fujita N, Tanioka K, Shiraiwa T, Hozumi Y, Naritsuka S, Kusunoki M: Scanning-tunneling-microscopy of the formation of carbon nanocaps on SiC(0 0 0 -1). Chem Phys Lett 2006, 423: 317. 10.1016/j.cplett.2006.03.029View Article
- Takagi D, Hibino H, Suzuki S, Kobayashi Y, Homma Y: Carbon Nanotube Growth from Semiconductor Nanoparticles. Nano Lett 2007, 7: 2272. 10.1021/nl0708011View Article
- Botti S, Asilyan CRL, Dominicis LD, Fabbri F, Orlanducci S, Fiori A: Carbon nanotubes grown by laser-annealing of SiC nano-particles. Chem Phys Lett 2004, 400: 264. 10.1016/j.cplett.2004.10.119View Article
- Botti S, Asilyan LS, Ciardi R, Fabbri F, Lortei S, Santoni A, Orlanducci S: Catalyst-free growth of carbon nanotubes by laser-annealing of amorphous SiC films. Chem Phys Lett 2001, 396: 1. 10.1016/j.cplett.2004.06.132View Article
- Uchino T, Bourdakos KN, de Groot CH, Ashburn P, Kiziroglou ME, Dilliway GD, Smith DC: Catalyst free low temperature, direct growth of carbon nanotubes. Proceedings of 2005 5th IEEE Conference on Nanotechnology 2005, 5: 1.
- Uchino T, Bourdakos KN, de Groot CH, Ashburn P, Kiziroglou ME, Dilliway GD, Smith DC: Metal catalyst-free low-temperature carbon nanotube growth on SiGe islands. Appl Phys Lett 2005, 86: 233110. 10.1063/1.1946191View Article
- Liu H, Takagi D, Ohno H, Chiashi S, Chokan T, Homma Y: Growth of Single-Walled Carbon Nanotubes from Ceramic Particles by Alcohol Chemical Vapor Deposition. Appl Phys Express 2008, 1: 014001. 10.1143/APEX.1.014001View Article
- Steiner SA, Baumann TF, Bayer BC, Blume R, Worsley MA, MoberlyChan WJ, Shaw EJ, Schlogl R, Hart AJ, Hofmann S, Wardle BL: Nanoscale Zirconia as a Nonmetallic Catalyst for Graphitization of Carbon and Growth of Single- and Multiwall Carbon Nanotubes. J Am Chem Soc 2009, 131: 12144. 10.1021/ja902913rView Article
- Bystrzejewski M, Bachmatiuk A, Thomas J, Ayala P, Huebers H-W, Gemming T, Borowiak-Palen E, Pichler T, Kalenczuk RJ, Büchner B, Rümmeli MH: Boron doped carbon nanotubes via ceramic catalysts. Phys Stat Sol RRL 2009, 3: 193. 10.1002/pssr.200903088View Article
- Bachmatiuk A, Bystrzejewski M, Schäffel F, Ayala P, Wolff U, Mickel C, Gemming T, Pichler T, Borowiak-Palen E, Klingeler R, Huebers H-W, Ulbrich M, Knupfer M, Haberer D, Büchner B, Rümmeli MH: Carbon nanotube synthesis via ceramic catalysts. Phys Stat Sol B 2009, 246: 2486. 10.1002/pssb.200982308View Article
- Liu B, Ren W, Gao L, Li S, Pei S, Liu C, Jiang C, Cheng H-M: Metal-Catalyst-Free Growth of Single-Walled Carbon Nanotubes. J Am Chem Soc 2009, 131: 2082. 10.1021/ja8093907View Article
- Huang S, Cai Q, Chen J, Qian Y, Zhang L: J Am Chem Soc. 2009, 131: 2094. 10.1021/ja809635sView Article
- Bachmatiuk A, Börrnert F, Grobosch M, Schäffel F, Wolff U, Scott A, Zaka M, Warner JH, Klingeler R, Knupfer M, Büchner B, Rümmeli MH: Investigating the graphitization mechanism of SiO2 nanoparticles in chemical vapor deposition. ACS Nano 2009, 3: 4098. 10.1021/nn9009278View Article
- Bachmatiuk A, Börrnert F, Schäffel F, Zaka M, Simha-Martynkowa G, Placha D, Schönfelder R, Costa PMFJ, Ioannides N, Warner JH, Klingeler R, Büchner B, Rümmeli MH: The formation of stacked-cup carbon nanotubes using chemical vapor deposition from ethanol over silica. Carbon 2010, 48: 3175. 10.1016/j.carbon.2010.04.055View Article
- Schneider JJ, Maksimova NI, Engstler J, Joshi R, Schierholz R, Feile R: Catalyst free growth of a carbon nanotube-alumina composite structure. Inorg Chim Acta 2008, 361(6):1770. 10.1016/j.ica.2006.10.025View Article
- Rümmeli MH, Kramberger C, Grüneis A, Ayala P, Gemming T, Büchner B, Pichler T: On the graphitization nature of oxides for the formation of carbon nanostructures. Chem Mater 2007, 19: 4105.View Article
- Haruta M: Size- and support-dependency in the catalysis of gold. Catal Today 1997, 36: 153. 10.1016/S0920-5861(96)00208-8View Article
- Rümmeli MH, Schäffel F, Kramberger C, Gemming T, Bachmatiuk A, Kalenczuk RJ, Rellinghaus B, Büchner B, Pichler T: Oxide-driven carbon nanotube growth in supported catalyst CVD. J Am Chem Soc 2007, 129: 15772.View Article
- Rümmeli MH, Schäffel F, Bachmatiuk A, Adebimpe D, Trotter G, Börrnert F, Scott A, Coric E, Sparing M, Rellinghaus B, McCormick PG, Cuniberti G, Knupfer M, Schultz L, Büchner B: Investigating the outskirts of Fe and Co catalyst particles in alumina-supported catalytic CVD carbon nanotube growth. ACS Nano 2010, 4(2):1146.View Article
- Yoshida H, Yoshida H, Takeda S, Uchiyama T, Kohno H, Homma Y: Atomic-Scale In-situ Observation of Carbon Nanotube Growth from Solid State Iron Carbide Nanoparticles. Nano Lett 2008, 8: 2082. 10.1021/nl080452qView Article
- Schäffel F, Täschner C, Rümmeli MH, Neu V, Wolff U, Queitsch U, Pohl D, Kaltofen R, Leonhardt A, Rellinghaus B, Büchner B, Schultz L: Carbon nanotubes terminated with hard magnetic FePt nanomagnets. Appl Phys Lett 2009, 94: 193107.View Article
- Vander Wal RL, Tichich TM, Curtis VE: Substrate-support interactions in metal-catalyzed carbon nanofiber growth. Carbon 39: 2277. 10.1016/S0008-6223(01)00047-1
- Bacon R, Bowman JC: Production and properties of graphite whiskers. Bull Am Phys Soc 1957, 2: 131.
- Takagi D, Kobayashi Y, Homma Y: Carbon Nanotube Growth from Diamond. J Am Chem Soc 2009, 131: 6922. 10.1021/ja901295jView Article
- Rao F, Li T, Wang Y: Growth of "all-carbon" single-walled carbon nanotubes from diamonds and fullerenes. Carbon 47: 353.
- Yu X, Zhang J, Choi W, Choi J-Y, Kim JM, Gan L, Liu Z: Cap Formation Engineering: From Opened C60 to Single-Walled Carbon Nanotubes. Nano Lett 2010, 10: 3343. 10.1021/nl1010178View Article
- Yao Y, Feng C, Zhang J, Liu Z: "Cloning" of Single-Walled Carbon Nanotubes via Open-End Growth Mechanism. Nano Lett 2009, 9: 1673. 10.1021/nl900207vView Article
- Lin J-H, Chen C-S, Rümmeli MH, Zeng Z-Y: Self-assembly formation of multi-walled carbon nanotubes on gold surfaces. Nanoscale 2010, 2: 2835. 10.1039/c0nr00256aView Article
- Lin JH, Chen CS, Rümmeli MH, Bachmatiuk A, Zeng ZY, Ma HL, Büchner B, Chen HW: Growth of Carbon Nanotubes Catalyzed by Defect-Rich Graphite Surfaces. Chem Mater 2010.
- Reilly PTA, Whitten WB: The role of free radical condensates in the production of carbon nanotubes during the hydrocarbon CVD process. Carbon 2006, 44: 1653. 10.1016/j.carbon.2006.01.018View Article
- Rümmeli MH, Bachmatiuk A, Scott A, Börrnert F, Warner JH, Hoffman V, Lin J-H, Cuniberti G, Büchner B: Direct low-temperature nanographene CVD synthesis over a dielectric insulator. ACS Nano 2010, 4: 4206.View Article
- Zhu MY, Wang JJ, Holloway BC, Outlaw RA, Zhao X, Hou K, Shutthanandan V, Manos DM: A mechanism for carbon nanosheet formation. Carbon 45: 2229. 10.1016/j.carbon.2007.06.017
- Wang JJ: Free-standing subnanometer graphite sheets. Appl Phys Lett 2004, 85: 1265. 10.1063/1.1782253View Article
- Dato A, Radmilovic V, Lee Z, Phillips J, Frenklach M: Substrate-Free Gas-Phase Synthesis of Graphene Sheets. Nano Lett 2008, 8: 2012. 10.1021/nl8011566View Article
- MacKenzie KJ, See CH, Dunens OM, Harris AT: Do single-walled carbon nanotubes occur naturally? Nat Nanotechnol 2008, 3: 310. 10.1038/nnano.2008.139View Article
- Fries M, Steel A: Graphite Whiskers in CV3 Meteorites. Science 2008, 320: 91. 10.1126/science.1153578View Article
- Nuth JA, Johnson NM, Manning S: A Self-Perpetuating Catalyst for the Production of Complex Organic Molecules in Protostellar Nebulae. Astrophys J Lett 2008, 673: L225. 10.1086/528741View Article
- Nuth JA, Johnson NM, Manning S: A Self-Perpetuating Catalyst for the Production of Complex OrganicMolecules in Protostellar Nebulae. In IAU Symp. 251, Organic Matter in Space. Edited by: Kwok S, Sandford S. New York: Cambridge University Press; 2008:403.
- Nuth JA, Kimura K, Lucas C, Ferguson F, Johnson NM: The formation of graphite whiskers in the primitive solar nebula. Astrophys J Lett 2010, 710: L98. 10.1088/2041-8205/710/1/L98View Article
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