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Carabineiro, S. Kinetics of Carbon Nanotubes. Encyclopedia. Available online: https://encyclopedia.pub/entry/6870 (accessed on 27 July 2024).
Carabineiro S. Kinetics of Carbon Nanotubes. Encyclopedia. Available at: https://encyclopedia.pub/entry/6870. Accessed July 27, 2024.
Carabineiro, Sónia. "Kinetics of Carbon Nanotubes" Encyclopedia, https://encyclopedia.pub/entry/6870 (accessed July 27, 2024).
Carabineiro, S. (2021, January 28). Kinetics of Carbon Nanotubes. In Encyclopedia. https://encyclopedia.pub/entry/6870
Carabineiro, Sónia. "Kinetics of Carbon Nanotubes." Encyclopedia. Web. 28 January, 2021.
Kinetics of Carbon Nanotubes
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This entry is adapted from the peer-reviewed paper 10.3390/nano11010143

Carbon formation on steel has recently become an active research area with several important applications, using either carbon nanotubes (CNTs) or graphene structures. The production of vertically aligned CNT (VACNT) forests with combined metals has been explored with important results. Detailed kinetics is the best approach to understand a mechanism. The growth behavior seems complex but can be simplified through the knowledge of the three more common alternative reaction mechanisms/routes.

CNTs growth Fe-steel catalysis Carbon nanotubes

1. Introduction

Epitaxial growth on solid surfaces has been studied in some detail. Three growth modes are known: Island, layer-plus-island, and layer-by-layer [1]. However, nucleation of graphene on Ni, Fe, and Cu at low temperatures (300–550 °C) occurs through C atoms bulk diffusion supplied by gas decomposition (Mechanism/Route I) or carbon black C atoms (Mechanism/Route II), that dissolve and keep their individuality, moving interstitially in the metal catalyst. Layer-by-layer growth occurs only in the pyrolytic route (Figure 1). The Tammann temperature of Cu (406 °C) is much lower than Ni, Co, and Fe[2]. Route I operates with Fe, Co, Ni, and Cu only, using C2H2 or low olefins[3].

Nanomaterials 11 00143 g003 550

Figure 1. Explanation of the three alternative catalytic mechanisms/routes of carbon formation from hydrocarbons over different temperature/pressure ranges. When more than one mechanism may operate, the faster one prevails (adapted from[4] with permission from MDPI). * With Cu: at 250 °C. ** Graphene functionalization properties are extensively studied today.

As mentioned above, detailed kinetics is the best approach to prove which mechanism is operating. The detailed research work on diffusion of atoms in and through solids published from 1920 to 1960 should be used, particularly to get data on H, C, N, and O bulk diffusion in transition and noble metals[5][6]. Diffusion in solids is a complex process, but diffusion of C, N, and O in transition metals is interstitial: The atomic radius of solute C and solvent (transition metal) is below 0.59, the usual condition for that type of diffusion to occur[5][6].

It is essential to perform the experimental work under steady-state deposition rates (initial solid-state adjustments have finished). When the flux is constant, the first Fick’s law applies:

J = −D dC/dx
 
where J is the flux and dC/dx is the concentration gradient. Two different phases may operate in the catalyst nanoparticle (gas side vs. CNT growth side), adjusting the solid-state geometry to a C flux steady-state operating regime[7].

 

The Arrhenius plots shown in Figure 1 evidence the change of rate determining step at about 700 °C. Explanation of that change has been recently reminded[4]. Every point in the Arrhenius plot is a register of a steady-state deposition rate experiment (kinetic linearity observed)[4], that is, a full steady state C formation experiment, lasting 2 or 3 h. The volcano shape maximum with Fe and steel occurs at higher temperatures than with Ni and Co. This is due to the lower rate of the 1st reaction step (catalytic surface reaction), so that the prevalence of a lower 2nd step (C bulk diffusion through the solid catalyst) only occurs at higher temperatures. The dependence of temperature of the reaction rate observed in the lower temperature side of the volcano plot with Ni was ~33 kcal/mole. This is the activation energy of C atoms bulk diffusion in Ni. That value and zero order gas pressure dependence of the C formation reaction rate were regarded as proof of the mechanism operating, as reported in 1971[4][8][9]. Baker et al. described in detail the TEM in-situ growth geometry of CNTs (no kinetic experiments) [10] and followed the mechanism proposed by Lobo and Trimm based in 160 kinetic experiments, using a CI Electronics microbalance adapted to automatically change ranges in long experiments, if required[11][8]. In 2011, Lobo, Figueiredo, and Bernardo summarized their approach to the mechanism in the early 1970s [12].

A successful kinetic study requires an initial transition: The change of weight is fast in the first few minutes and then decreases to a sustained rate (kinetic linearity, as mentioned above). Our experiments with iron and steel were initiated at a lower temperature (ex. 500 °C) for 2 h. After that the temperature was increased by stages (ex. 15 °C) allowing enough time at each stage to confirm a steady state operating (straight line in the weight register). The initial transition may include phase changes of the nanoparticle catalyst bulk[7]. At lower temperatures, the prevailing bulk phase with Ni is the metal itself, but with iron it is Fe3C. Latorre et al. proposed a phenomenological kinetic model and discussed the nucleation and growth of CNTs in some detail[13].

Ermakova et al.[14] studied carbon formation from CH4/H2 using Fe on various supports: SiO2, Al2O3, and ZrO2 in the range 650–800 °C. The maximal carbon yield was obtained with SiO2. Metal filled carbon tubes were frequently filled with Fe particles and commented: “That can be hardly explained unless the quasi-liquid state of the metal is assumed”, and concluded that a high fluidity of iron-carbon particles was observed above 640 °C. However, the explanation is the sintering-like behavior of the nanoparticles due to contact interaction[15]. The sintering temperature of Fe is 632 °C.

Puretzky et al. [16][17] studied the kinetic CNTs’ growth using acetylene/Ar/H2/in the range 550–900 °C. These authors used multilayer metal films of 10nm Al and Fe or Mo as catalysts and a flow of C2H2 (6 sccm) diluted in Ar (ex: 2000 sccm) and H2 (ex: 400 sccm)[16]. The reason for this gas dilution can be understood by our recent analysis of high temperature carbon formation kinetics[18]. Low hydrocarbon partial pressure is the key to keep Route II operating at higher temperatures with a faster rate and avoiding pyrolytic graphene layers deposition (Route III, pyrolytic). In that study, a volcano shape of the Arrhenius plots of the rates vs. temperature (check ref.[16], Figures 13, 21, and 22), but the orders of reaction were not evaluated. In our studies, the orders of reaction were always evaluated experimentally. With that information, the alternative mechanisms operating were more easily distinguished. The two sides of the volcano correspond to the same mechanism (Route I, Catalytic), but with a change of the rate-determining step from C bulk diffusion to surface reaction decomposition of the gas reactant (C2H2 and low olefins, only). The other C formation gases only operate at higher temperatures by impingement of pyrolytic formed carbon (C2,C3…), C atoms entering the bulk of the catalyst and growing catalytically on the other side of the nano-particle[4]. In the studies of Puretzky et al., the reason a volcano shape was observed in the plot of the variation of the growth rates as a function of temperature was attributed to acetylene flow rates[17]. This is not correct. They did not measure reaction orders (alternative gas pressure steady-state experiments). The reaction order changes from zero (temperatures below the volcano maximum) to one (at temperatures above the maximum)[11][8]. This is the reason for the volcano shape observed.

The activity of Cu has been studied in detail by Shaikjee et al. using C2H2 at 195 °C and 250 °C[19]. The Tammann temperature of Cu is 405 °C. The absence of data on CNTs formation using Cu via Route II may be related to the stability of the nanoparticles shape.

Overall knowledge of the CNTs and graphene alternative growth mechanisms[3][8][18] is important to optimize rate, structure, and desired properties. Route I operates with acetylene and C2 to C4 olefins and CO. At higher temperatures, CNTs can be formed by route II only.

Studies on C formation on Ni, Co, and Fe in the 70′s were mainly performed to minimize the problems in the steam-reforming industry. Ni-Cu catalysts were used to reduce the problem, but still the need to stop the production from time to time due to catalyst deactivation by carbon formation was costly. CNTs were observed to grow easily from transition metals[11], but their properties were not known at the time. Carneiro, Baker, and co-authors studied CNTs’ growth on Fe-Ni and Fe-Cu from CO/H2 at ~700 °C[20][21]. They studied the structure of the CNTs formed. No kinetic studies were reported. An update of the observed kinetics of CNTs growth was published by Lobo[3].

The wider use of CNTs for many purposes and industrial production started after the work of Iijima in 1991[22]. Single layer CNTs were produced in 1993 by Iijima[23] and Bethune[24].

Roumeli recently published a study of vertically aligned CNT forests grown on stainless steel surfaces, including adhesion tests between the tubes and the steel substrate to test their adhesion performance using 4 types of steels[25].

Concerning graphene, the deposition of layers at high temperatures is a transition from the CNTs growth by the hybrid route to the pyrolytic route, but the deposition rate observed follows the same Arrhenius plot line[18]: Almost a paradox (check Figure 1, (A)). This must be understood—it is a change of mechanism with a continuous line in the Arrhenius plot: At lower temperatures, C2/C3 rate of deposition controls the rate; at higher temperatures, C2/C3 rate of deposition dominates and covers the catalyst surface with graphene layers–pyrolytic route.

Koyama and Katsuki et al. produced carbon fibers via pyrolysis of benzene and naphthalene at temperatures above 1000 °C in 1972[26][27]. Tibbetts reported the production of carbon fibers by pyrolysis of CH4 in stainless steel tubes in the range 950–1075 °C [28]. Figueiredo and co-workers studied carbon formation from CH4 using Fe-Ni, Fe-Co, and Ni-Co in the range of temperatures 650–950 °C[29] and using Fe-Mo, in the range of temperatures 500–800 °C . The carbon formation reaction using methane does not operate by the catalytic route. Only via gas pyrolysis and the hybrid route the formation of CNTs is possible. High temperatures are required.

2. CNT Forests Growth Optimization vs. Kinetics and Mechanisms

Yamazaki et al.[30], Iwasaki et al.[31], and Robertson et al.[32][33][34][35][36] studied the growth of vertically aligned CNTs in detail (check Figure 2A,B). In this case, an extra kinetic step is present: Diffusion of the reactant gas through the thin space between the CNTs. Could that step be rate-limiting when the CNTs are very long? CNT forests are sometimes grown from CH4. However, in this case, mechanism I (catalytic) is not operative. Mechanism II, operating at higher temperatures, is required (check Figure 1 and Table 2). Forests of CNTs (check Figure 2B) became recently the object of growth optimization to increase production and reduce costs. Lee et al. [37]. Bedewy et al.[38], Park et al.[39], Meshot et al. [40]and Yang et al.[41][36] analyzed the CNT’s forest growth, recently.

Nanomaterials 11 00143 g005 550

Figure 2. (A) Growth of CNT forests. Reprinted from Iwasaki et al.[31] with permission from ACS. (B) Closed Packed CNT Forests. Reprinted from Robertson et al.[32] with permission from Wiley.

Underlayer vs. nanoparticle size, spacing, and stability during reaction have been studied by several authors[42][43][44]. Delzeit et al. studied Fe on a thick Ir underlayer, trying also Mo added to Fe. They used CO as a reacting gas and had to use 900 °C as reaction temperature[42]. In fact, mechanism I is not active with CO, and only mechanism II operates. With Fe, that temperature is required. Burt et al. used Fe on Al2O3 grains on Si and SiO2 substrates, but used ethanol as a reacting gas[43]. So only reaction Route II is operative. The reaction was performed at 800 °C with 4% H2. Low pressures are more effective to reach higher rates when route/mechanism II is operating. This seems a paradox, but has been explained in detail, recently[18].

A good explanation for the growth of the size of the Fe nanoparticles (“larger diameter”), causing enlargement of the CNTs diameter, shown in Figure 2A at 700 °C, is sintering-like behavior of solid-solid contacts above the Tammann temperature of Fe (632 °C), as remarked above (point 5). The rates of CNTs growth from particles with different diameter d are proportional to 1/d2. The diffusion distances are proportional to 1/d, and the growth perimeter is also proportional to 1/d.

This proportionality helps us to understand that in a sample with various nanoparticle sizes, and so with different growth rates, the kinetic model applies: The effect of changing pressure and/or temperature applies overall in the system. The detailed study of Nessim et al. in 2008 tuning vertically aligned CNTs (VACNTs) diameter growth on Fe can be better understood considering that they operated at 770 °C, well above the TTa of Fe[45].

Baker proposed that C bulk diffusion through Ni particles is due to a temperature gradient[10][46]. We consider this to not be correct[3]. The fact that the growth rate on Ni below 550 °C is not due to a temperature gradient can also be avoided, knowing that the rates are exactly the same with C2, C3, and C4 olefins, and C formation from C4H4 is endothermic[3]. However, the main error is the assumption that heat, being a consequence of the reaction (exothermic), may be its cause. This infringes on the causality principle. Baker’s proposal was sustained for 20 years[46]. C bulk diffusion is due to a dissolved C concentration gradient between the two operating sides of the catalyst[4][8].

3. CNTs Application Areas

Thin graphene films can be formed following route/mechanism III (pyrolysis) but operating at the “border” of the required temperature and pressure conditions (slow deposition rates). Good graphene thin films have been formed by Sarno et al.[47], Romero et al. [48], and more recently by Um et al. [49]. Additionally, a book by Venables on “Introduction to surface and thin film processes” is available[1].

CNTs are an important basis nowadays for applications in many areas. Harris summarized those uses, covering electronic, mechanical, optical, thermal, chemical, and biology areas[50].

The studies by Treacy et al. in 1996 on the changes of mechanical properties showed that CNTs might be useful in strong, lightweight composite materials[51]. Exceptionally high young modulus were observed for individual CNTs. The very high number of citations reveals the importance of this finding. Gao et al. and Adhikary et al. recently revised the mechanical properties and microstructure of cement-based materials searching for the best structure of the CNTs to its reinforcement [52]. A book by Guceri and Gogotsi from an ASI NATO meeting on nanofibrous materials is available[53].

The electrical conductivity of the CNTs is important for several uses. The studies by Ebbesen et al. published in 1996 on individual electronically properties of CNTs have stimulated that study and optimization for particular applications [54]. Abrupt jumps in conductivity were observed as temperature varied. The number of citations of these articles evidences the growing use of CNTs in electronics. Increase of electrical conductivity of Fe CNT sheets. Enhancement of electrical conductivity adding Cu to Fe has been recently reported by Earp et al. [55].

CNTs have recently being tested with success in drug delivery, particularly in cancer treatment, and may progressively replace the current treatments of surgery, radiation therapy, and chemotherapy.

References

  1. Venables, J.A. Introduction to Surface and Thin Film Processes; Cambridge University Press: Cambridge, UK, 2000.
  2. Lobo, L.S.; Carabineiro, S.A.C. Review: Explaining bamboo-like carbon fiber growth mechanism: Catalyst shape adjustments above tammann temperature. C 2020, 6, 18.
  3. Lobo, L.S. Catalytic carbon formation: Clarifying the alternative kinetic routes and defining a kinetic linearity for sustained growth concept. React. Kinet. Mech. Catal. 2016, 118, 393–414.
  4. Lobo, L.S. Mechanism of catalytic CNTs Growth in 400–650 °C Range: Explaining volcano shape Arrhenius plot and catalyt-ic synergism using both Pt/Pd and Ni, Co or Fe. C 2019, 5, 42.
  5. Barrer, R.M. Diffusion in and Through Solids; Cambridge University Press: Cambridge, UK, 1941.
  6. Budnikov, P.P.; Ginstling, A.M. Principles of Solid-State Chemistry. Reactions in Solids; Gordon Breach: New York NY, USA, 1968.
  7. De Jong, K.; Geus, J.W. Carbon nanofibers: Catalytic synthesis and applications. Cat. Rev. Sci. Eng. 2000, 42, 481–510.
  8. Lobo, L.S.; Trimm, D.L. Studies of carbon formation on metals using a vacuum microbalance. In Progress in Vacuum Micro-balance Techniques; Heyden and Son: London, UK, 1972; Volume 2.
  9. Lobo, L.S. Carbon Formation from Hydrocarbons on Metals. Ph.D. Thesis, Imperial College, London, UK, 1971.
  10. Baker, R.T.K.; Barber, M.A.; Harris, P.S.; Feats, F.S.; Waite, R.J. Nucleation and growth of carbon deposits from nickel cata-lyzed decomposition of acetylene. J. Catal. 1972, 26, 51–62.
  11. Lobo, L.S.; Trimm, D.L. Complex temperature dependencies of the rate of carbon deposition on nickel. Nat. Phys. Sci. 1971, 234, 15–16.
  12. Lobo, L.S.; Figueiredo, J.L.; Bernardo, C.A. Carbon formation and gasification on metals. Bulk diffusion mechanism: A re-assessment. Catal. Today 2011, 178, 110–116.
  13. Latorre Romeo, E.; Canzana, F.; Ubieto, T.; Royo, C.; Villacampa, J.I.; Monzón, A. CNT Growth by CVD: A phenomenolog-ical kinetic model. J. Phys. Chem. C 2010, 114, 4773–4782.
  14. Ermakova, M.A.; Ermakov, D.Y.; ChuvilinAL.; Kuvshinov, G. Decomposition of methane over iron catalysts at the range of moderate temperatures: The influence of structure of the catalytic systems and the reaction conditions on the yield of car-bon and morphology of carbon filaments. J. Catal. 2001, 2, 183–197.
  15. Lobo, L.S.; Carabineiro, S.A.C. Mechanism of CNTs and graphene growth: Kinetics versus thermodynamics. C 2020, 6, 0067.
  16. Puretzky, A.A.; Geohegan, D.B.; Jesse, S.; Ivanov, I.N.; Eres, G. In situ measurements and modeling of CNTs arrays growth kinetics during CVD. Appl. Phys. A 2005, 81, 223–240.
  17. Kayastha, V.K.; Yap, Y.K.; Pan, Z.; Ivanov, I.N.; Puretzky, A.A.; Geohegan, D.B. High-density vertically aligned MWCNTs with tubular structures. Appl. Phys. Lett. 2005, 86, 253105.
  18. Lobo, L.S.; Sonia, S.A.C. Carbon formation at high temperatures (550–1400 °C): Kinetics, alternative mechanisms and growth modes. Catalysts 2020, 10, 465.
  19. Shaikjee, A.; Franklyn, P.J.; Coville, N.J. The use of electron microscopy tomography to correlate copper catalyst particle morphology with carbon fibered catalytic CVD. Carbon 2011, 49, 2950–2959.
  20. Carneiro, O.C.; Kim, M.S.; Yim, J.B.; Rodriguez, N.M.; Baker, R.T.K. Growth of graphite nanofibers from iron-copper catalyzed decomposition of CO/H2 mixtures. J. Phys. Chem. B 2003, 107, 4237.
  21. Carneiro, O.C.; Anderson, P.E.; Rodriguez, N.M.; Baker, R.T.K. Synthesis of high purity narrow-width CNTs. Carbon 2012, 50, 3200–3209.
  22. Iijima, S. Helical microtubules of graphitic carbon. Nature 1991, 354, 56–58.
  23. Iijima, S. Single-shell carbon nanotubes of 1-nm diameter. Nature 1993, 363, 603–605.
  24. Bethune, D.S.; Kiang, C.H.; de Vries, M.S.; Gorman, G.; Savoy, R.; Vazquez, J.; Beyers, R. Bethune Co-catalyzed growth of CNTs with single-atomic-layer walls. Nature 1993, 363, 605–607.
  25. Roumeli, E.; Diamantopolos, M.; Serra-Garcia, M.; Johanns, P.; Parcianello, G.; Daraio, C. Characterization of vertically aligned carbon nanotube forests grown on stainless steel surfaces. Nanomaterials 2019, 9, 444.
  26. Koyama, T. Formation of carbon fibers from benzene. Carbon 1972, 10, 757.
  27. Katsuki, H.; Matsunaga, K.; Egashira, M.; Kawasumi, S. Formation of carbon fibers from naphthalene on some sul-fur-containing substrates. Carbon 1981, 19, 148.
  28. Tibbetts, G.G. Carbon fibers produced by pyrolysis of natural gas in stainless steel tubes. Appl. Phys. Lett. 1983, 42, 666–668.
  29. Mendez, A.; Freitas, M.M.A.; Figueiredo, J.L.F. Synthesis of carbon filaments and nanotubes on graphitic substrate: Optimi-zation studies. Carbon 2006, 44, 2330–2356.
  30. Yamazaki, Y.; Katagiri Sakuma, N.; Suzuki, M. Synthesis of a closed packed CNT Forest by a multi-step growth method using plasma-based CVD. Appl. Phys. Express 2010, 3, 5.
  31. Iwasaki, T.; Robertson, J.; Kawarada, H. Mechanism analysis of interrupted growth of SWCNTs arrays. Nano Lett. 2008, 8, 886–890.
  32. Robertson, J.; Zhong, G.; Esconjauregui, S.; Zhang, C.; Fouquet, M.; Hofmann, S. Chemical vapor deposition of CNT forests. Phys. Status Solidi B 2012, 249, 2315–2322.
  33. Zhong, G.; Warner, J.H.; Fouquet, M.; Robertson, A.W.; Chen, B.; Robertson, J. Growth of ultrahigh density SWCNT forests by improved catalyst design. ACS Nano 2012, 6, 2893–2903.
  34. Robertson, J. Heterogeneous catalysis model of growth mechanisms of CNTs, graphene and silicon nanowires. J. Mater. Chem. 2012, 22, 19858.
  35. Bayer, B.C.; Fouquet, M.; Blume, R.; Wirth, C.T.; Wetherup, R.S.; Ogata, K.; Knop-Gericke; Schlogl, R.; Hofmann, S.; Robertson, J. Co-catalytic solid-state reduction applied to CNT growth. J. Phys. Chem. C 2012, 116, 1197–1113.
  36. Zhong, G.; Yang, J.; Sugime, H.; Rao, R.; Zhao, J.; Liu, D.; Harutyunyan, A.; Robertson, J. Growth of high quality, high density single walled CNT forests on copper foils. Carbon 2016, 98, 624–632.
  37. Lee, J.; Abdulhafez, M.; Bedewy, M. Decoupling catalyst dewetting, gas decomposition, and surface reactions in CNT forests growth reveals dependence of density on nucleation temperature. J. Phys. Chem. C 2019, 123, 28726–28738.
  38. Bedewy, M.; Meshot, E.R.; Hart, A.J. Diameter-dependent kinetics of activation and deactivation in carbon nanotube popu-lation growth. Carbon 2012, 50, 5106–5116.
  39. Park, J.S.; Schmidt, A.J.; Bedewy, M.; Hart, A.J. Measurement of carbon nanotube microstructure relative density by optical attenuation and observation of size-dependent variations. Phys. Chem. Chem. Phys. 2013, 15, 11511–11519.
  40. Meshot, E.R.; Bedewy, M.; Lyons, K.M.; Woll, A.R.; Juggernauth, K.A.; Tawfick, S.; Hart, A.J. Measuring the lengthening kinetics of aligned nanostructures by spatiotemporal correlation of height and orientation. Nanoscale 2010, 2, 896–900.
  41. Zhong, G.; Xie, R.; Yang, J.; Robertson, J. Single-step of high-density carbon nanotube forests on metallic Ti coatings through catalyst engineering. Carbon 2014, 67, 680.
  42. Delzeit, L.; Chen, B.; Cassel, A.; Stevens, R.; Nguyen, C.; Meyyappan, M. Multilayered metal catalyst for controlling the density of single-walled CNT growth. Cem. Phys. Lett. 2001, 348, 368–374.
  43. Burt, D.P.; Whyte, M.; Weaver, J.M.R.; Glide, A.; Edgeworth, J.P.; Maspherson, J.V.; Dobson, P.S. Effects of metal underlayer grain size on carbon nanotube growth. J. Phys. Chem. C 2009, 113, 34.
  44. Nessim, G.D.; Acquaviva Seita, M.; O’Brien Thompson, C.V. The critical role of the underlayer material and thickness in growing VACNTS and nanofibers on metallic substrates by chemical vapour deposition. Adv. Funct. Mater. 2010, 20, 1306–1312.
  45. Nessim, G.D.; Hart, J.; Kim, J.S.; Acquaviva, D.; Oh, J.; Morgan, C.D.; Seita, M.; Leib, J.S.; Thompson, C.V. Tunning of verti-cally-aligned CNT diameter and areal density through catalyst pre-treatment. Nano Lett. 2008, 11, 3587–3593.
  46. Baker, R.T.K. Catalytic growth of carbon filaments. Carbon 1989, 27, 315–323.
  47. Sarno, M.; Cirilo, C.; Piscitelli, R.; Ciambelli, P. A study of the key parameters, including the crucial role of H2 for uniform graphene growth on Ni foil. J. Mol. Catal. A 2013, 366, 303–314.
  48. Romero, P.; Oro, R.; Campos, M.; Torralba, J.M.; Villoria, R.G. Simultaneous synthesis of VACNTs and amorphous carbon thin films on stainless steel. Carbon 2015, 82, 31–38.
  49. Um, J.W.; Kim, S.-Y.; Lee, B.-H.; Park, J.B.; Jeong, S. Direct writing of graphite thin film by laser-assisted CVD. Carbon 2020, 169, 163–171.
  50. Harris, P.J.F. Carbon Nanotubes Science. Synthesis, Properties and Applications; Cambridge University Press: Cambridge, UK, 2009.
  51. Treacy, M.; Ebbesen, T.; Gibson, J. Exceptional high young modulus observed for individual CNTs. Nature 1996, 381, 678–680.
  52. Adhikary, S.K.; Rudzionis, Z.; Rajapriya, R. The effect of carbon nanotubes on the floeability, mechanical, microstructural and durability properties of cementite composite: An overview. Sustainability 2020, 12, 8362.
  53. Guceri, S.; Gogotsi, Y.G. Nanoengineered Nanofibrous Materials; Springer: Dordrecht, The Netherlands, 2004.
  54. Ebbesen, T.W.; Lesec, H.J.; Hiura, H.; Bennet, J.W.; Chemi, H.F.; Thio, T. Electrical conductivity of individual carbon nano-tubes. Nature 1996, 382, 54–56.
  55. Earp, B.; Dunn, D.; Phillips, J.; Agrawal, R.; Ansell, T.; Aceves, P.; De Rosa, I.; Xin, W.; Luhrsa, C. Enhancement of electrical conductivity of CNT sheets through Cu addition using reduction expansion synthesis. Mat. Res. Bull. 2020, 131, 110969.
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