Carbon Nanomaterials And Fullerene Synthesis Assignment Sample

Carbon Nanomaterials And Fullerene Synthesis Assignment

Carbon nanomaterials

Introduction

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There are three forms of carbon nanomaterial allotropes: graphene, carbon nanotubes, and fullerenes. They are all heat and electricity sensitive, as well as good conductors of thermal and electrical energy. They may appear to be similar compounds, yet they differ in terms of structuralism, features, and properties. Only their incidences are the same. These three types of nano materials are discussed in this assignment and synthesis of fullerene will also be highlighted in the next chapter with defined mechanisms. 

Carbon nanotubes

Carbon nanotubes (CNTs) are one-dimensional allotropic compounds of carbon. These are classified into three varieties based on the structure of their bending along distinct axes: “zigzag”, “armchair”, and “chiral” (Kalhor and Yahyazadeh, 2019). CNTs can sometimes be multi-layered or single-layered. CNTs could be employed as lubricating substances. Buckyballs, for fact, are excellent lubricants due to their rounded form. The porous form of CNTs might make them suitable for administering medication. These compounds are also used for chemical sensing. CNTs are extremely lightweight and durable, and they may function as semiconductors or conductors. Not only electricity, they are also able to transfer heat and therefore these are also used for the heat transition compounds in electronic devices.

Graphene

Graphene is indeed a carbon allotrope that is categorized as a semimetal due to the presence of metallic characteristics in those compounds. This is a two-dimensional carbon nanomaterials. It is singular layered and composed of six carbon molecules that come together to generate a hexagonal lattice-shaped arrangement. Because of its numerous amazing qualities, graphene is however regarded as the “wonder substance” (Asadian et al. 2019). It would also be the most resilient substance known to humanity, although it is very pliable and flexible. Graphene is almost a supersaturated carbon molecule to its one-atom thickness, yet it really is an outstanding conductor of heat and electricity.

Figure 1: (a) graphite, (b) single layer of graphene

(Source: researchgate.net)

Fullerene: 

Fullerenes, identified in 1985, are the third most pure allotrope of carbon substance known after graphite as well as diamond. These are composed completely of sp2 hybridized carbon atoms organized in pentagonal and hexagonal lattices. The pentagonal circles impose stress upon that framework, which would be relieved by “out-of-plane” distortion or bending at every pentagon. Because of its bending nature in the carbon network, fullerene monomers have a cylindrical caged arrangement. The most robust circle structure follows the Isolation of Pentagon Principle, which states that no 2 consecutive pentagons inside a sustainable fullerene may be nearby. A material's amount of pentagons is set at 12 since this offers enough bending to produce a compact sphere. 

Figure 2: Molecular structure of fullerene, (a) C60, (b) C70

(Source: Goel et al. 2002)

Graphene nano materials are polymeric composed of hexagonal-shaped carbon molecules, each of which is connected to four additional carbon atoms and possesses an electron in their interstitial position. This is the most fundamental of all allotropic carbon nano materials. The production of 0-dim Fullerenes is caused by stretching and bending of something like the graphene sheets (Stevenson, 2021). The production of 1-dim Carbon Nanotubes arises by rolling the sheets to its axis. The 3-dim Graphite is created by overlapping graphene plates.

Similarities

The allotropes of carbon nano materials are generally three types of and those are graphene, carbon nanotubes, and fullerenes. They all are sensitive to heat and electricity and good conductors of thermal and electrical energies. Maybe they look like similar compounds but they are different in structuralism, characteristics, and properties. Only their occurrences are the same. Maybe they contain similar multiple carbon atoms bonding rather they are different according to their properties and structure. Their structures are cage-like which are sometimes spiral, sometimes layered, or multilayered.

Differences

CNTs, fluorene, and graphene are carbon allotropes with distinct electrical, mechanical, and other physical characteristics. Graphene is a 2D nanomaterial substance composed of carbon molecules organized in a hexagon or honeycomb lattice. They are different by their structures, properties and characteristics although they are similar according to their occurrences.

1. Carbon nanotubes (CNTs) are 1D allotropic compounds of carbon nano materials, whereas graphene is indeed a 2D single sheet of carbon nano materials. The 3-dim Graphite may be created by layering graphene sheets. The 0-dim fullerenes can be formed by twisting and bending of the 2D graphene. 
2. The major distinction is that graphene seems to be a singular thin layered 2D sheet, whereas carbon nanotubes are a thin sheet rolled into a 3D tubular or cylindrical structure. Despite the fact that they have many comparable qualities, each has its own set of purposes and uses.
3. In terms of capability, graphene outperforms carbon nanotubes and just about any other recognized nanofillers in transmitting its outstanding resilience and dynamic qualities to a host lattice.
4. According to the composition, carbon nanomaterials are differentiated into four divisions which are a) inorganic based nanomaterials, b) organic based nanomaterials, c) carbon based and d) composite based nanomaterials.

Figure 3: Different types of carbon nanomaterials

(Source: ars.els-cdn.com)

Fullerene synthesis and mechanisms

Although fullerenes had first been definitively recognized as flame constituents, fullerene-forming burning processes were the topic of intense research. Several flames have indeed been analyzed and reported in terms of fullerene contents in an effort to obtain the ideal circumstances of fullerene production. In parallel, a significant attempt has been done to anticipate and validate the mechanics of fullerene synthesis in order to truly comprehend and create ideal flame settings. The overarching objective of this burning research is to one day find a combustor appropriate for the huge generation of fullerene nanomaterials and fullerene carbon soot.

Fullerene nanomaterials were discovered in flames for the very first time in 1986, and conjugated polymers ions were discovered in plain premixed “acetylene-oxygen” and “benzene-oxygen” flames in 1987. Yet, it wasn't before 1991 when fullerenes compounds were discovered in flame-recovered materials. Soot formed by reduced pressure blended “benzene/oxygen/argon” fires included fullerenes. This research yielded macroscopic amounts of C60 and C70 as well as established burning as a viable approach for fullerene nanomaterials synthesis (Martin et al. 2022). According to the findings of this study, fullerene production was strongly sensitive to heat, stress, residency period, and fuels to air mixture ratio. Factors used to regulate these variables, such as cylinder chamber stress, dispersion, and cool gas velocities, have been varied over a broad scale to generate different flames that define fullerene formation. The production of C60 in such investigations varied from 0.003 percent to 9 percent (by proportion) of something like the gathered soot as well as from 0.001 percent to 0.7 percent (by quantity) of elemental composition supplied. Furthermore, fullerenes polymers as big as C116 were seen during identical flame tests conducted by many others. Fullerene production has indeed been researched in sparks produced by the burning of different organic fuels. This would include “naphthalene”, “butadiene”, “toluene”, and organic compounds containing halogens. This has recently been demonstrated that benzene creates the most fullerenes of any naturally derived fuel; however this production can be increased either by inclusion of something like a chloride component.

According to Goel et al. (2002), premixed and diffused laminar “benzene/oxygen/argon” flames had recently been investigated in more depth. Mixture flames investigations show two different zones of fullerene polymeric compound synthesis and degradation as the altitude just above burner increases. Fullerene production has also been shown to be highly associated with gas flow rate, although having just a minor impact on stress and dispersion. The impact of speed is indeed an oblique link since flow rate influences temperatures inside the flames, which affect fullerene synthesis. According to diffusing flames experiments, fullerene production increases just at the stoichiometric top of something like a flame but decreases with rising argon diluting. According to the findings, fullerene production is closely associated with flame height and heat. Both of these variables are connected to pressure inside the chamber, argon dispersion, and cold gaseous fueling speed. Fullerene outputs of 0.5 percent (by weight) of total organic carbon supplied were reported, however this figure might be greater.

Even though the process for fullerene synthesis in combustion processes has not really been completely explained and is being debated, a number of potential paths have indeed been postulated. These processes, which may be classified as gas-phase or solid-phase processes, all entail interactions or translocations of hydrocarbon chains that are thought to be involved in fires. It must be emphasized that perhaps the hypothesized processes don't really explain precise interactions among individual compounds, but rather give general conceptual frameworks of something like the sorts of events that might happen to make fullerenes. Fullerenes are hypothesized to originate in the gaseous state primarily via molecular mass growth processes closely resembling this creation of “polycyclic aromatic hydrocarbons” (PAH) and filth (Leon et al. 2021). These processes can entail the attachment of reduced molecular masses of the species, including such acetylene, to reactive receptors on bigger aromatics together in different stages, or the clotting of two big particular PAH monomers and/or carbon bunches. The step-wise adding process for fullerenes, like the HACA methods postulated for PAH synthesis, would include the extraction of the H-atom from such a heterocyclic compound. This would have been preceded by C2H2 insertion and carbonylation, which would result in ringed closures. This process could ultimately lead to birdcage closing as well as the development of a fullerene monomer as the structure grew large sufficiently. Two or even more bigger aromatic compounds (most probably twisted, suggesting the existence of pentagonal ring) joining together along with hydrogen removal to straight from fullerenes would have been the dynamic coagulate process. Either of these techniques are considered to participate in fullerene formation in combustion, however it is also claimed that coagulate is indeed the major approach. Another hypothesized gaseous phase construction method includes the zippering together with one or more hydrocarbon chains, accompanied by intramolecular reorganization to generate a persistent fullerene structure. Inside one way, 2 PAH compounds (most probably flat) orient themselves outskirts such that they may be readily joined as if they've been zipped up. Such zippering creates a shuttered structure with the right amount of pentagons, which subsequently rearranges to produce the most permanent polymorph of the fullerene nanoparticles (Chang et al. 2019). A big ribbon-shaped polymer, including such “polyacetylene” or a PAH with five-membered loops, would wrap up then zip to itself in a comparable hypothesized mechanism. Once buttoned up, the molecule might go through intramolecular reconfiguration, benzene group interaction, and/or hydrogen removal if required. Although the first zippering process is seen to be possible in fires, the other is thought to be implausible. Fullerenes may also be generated in combustion via compressed solid state processes, according to one theory. They were discovered as byproducts of inner rearranging processes just on surfaces of carbon nanoparticles exposed to thermal treatments and electron diffraction illumination inside an inert environment. This research shows that pentagonal flaws form in hexagonal strips of graphites, and it implies that somehow a similar mechanism may develop on soot nanoparticle layers on fires. The development of heterogeneous reactions similar towards the gaseous phase processes outlined is perhaps a second best option for robust creation. Fullerene precursor’s particles might adhere (mechanical or chemical) to something like a soot particulate, go through the cages closing processes, and then will be eventually released further into gaseous form. However, a precursor component does not have to attach to something like soot particles since fullerene formation events can happen with such a PAH or graphite compound that is currently at its surface. 

Figure 4: HPLC chromatogram of the extracted soot at the stage two flames at 60 mm HAB

(Source: Goel et al. 2002)

Figure 5: Chromatogram of the extracted soot from McKinnon flame at 50 mm HAB

(Source: Goel et al. 2002)

Figure 6: Chromatogram of the extracted soot from McKinnon flame at 5.8 mm HAB

(Source: Goel et al. 2002)

The proportion of fullerenes inside the burning reduced quickly just after the supplementary fuel injection system inside the 2 burns with shooting main flames but never completely restored to prior proportions throughout the region investigated (Pan et al. 2020). Combustion with such a nonsooting basic flames, that seems to be, flaming with really no fundamental fullerene synthesis, produced no carbon and hydrogen whatsoever, save in as little during lengthy residency durations. HPLC chromatographic analysis for multiple specimens revealed that the additional fuels may well be generating circumstances akin towards the early phases of something like the “McKinnon flame”, a solitary blended spark known to generate fullerenes.

Evidence of fullerenes contents in the soot extracts

 (a) Concentration of fullerenes in condensable materials, and (b) in cold probed gas in different laminar diffusion flames at p= 20 torr

(Source: Goel et al. 2002)

The above figure proves the existence of fullerenes in the soot extract produced due to combustible flames. Goel et al has proved that the soot extracts contain a reasonable amount of fullerenes molecules at 20 torr pressure which are also an allotrope of carbon in his paper “Combustion synthesis of fullerenes and fullerenic Compounds”.

 Concentration of fullerenes at 40 torr in condensable mass and cold probed liquid

(Source: Goel et al. 2002)

It has been seen that the flame length increases with increasing pressure while simultaneously flame diameter decreases. Intensity of flame increases with higher pressure. But, the concentration of fullerenes decreases with increasing pressure. Soot extracts contain maximum fullerenes if they are produced at lower pressure and lower dilutions at a slower flame.

Outlook

Carbon nanomaterials are used vastly in different fields including medicines, advanced diagnosis, chemical sensing, heat conductors, electricity conductors, etc because of their variant properties. But one of the most defined problems is decomposition of the compounds in the environment. These are non biodegradable and therefore, they may create serious impacts for the environment. These compounds do not mix with the environment. 

 References

Journals

Chang, Y., Chang, Y., Zhu, X., Zhou, X., Yang, C., Zhang, J., Lu, K., Sun, X. and Wei, Z., 2019. Constructing High?Performance All?Small?Molecule Ternary Solar Cells with the Same Third Component but Different Mechanisms for Fullerene and Non?fullerene Systems. Advanced Energy Materials, 9(16), p.1900190.

Pan, Y., Liu, X., Zhang, W., Liu, Z., Zeng, G., Shao, B., Liang, Q., He, Q., Yuan, X., Huang, D. and Chen, M., 2020. Advances in photocatalysis based on fullerene C60 and its derivatives: Properties, mechanism, synthesis, and applications. Applied Catalysis B: Environmental, 265, p.118579.

Kazemzadeh, H. and Mozafari, M., 2019. Fullerene-based delivery systems. Drug Discovery Today, 24(3), pp.898-905.

Lee, S.M., Kumari, T., Lee, B., Cho, Y., Lee, J., Oh, J., Jeong, M., Jung, S. and Yang, C., 2020. Horizontal?, Vertical?, and Cross?Conjugated Small Molecules: Conjugated Pathway?Performance Correlations along Operation Mechanisms in Ternary Non?Fullerene Organic Solar Cells. Small, 16(5), p.1905309.

Leon, G., Martin, J.W., Bringley, E.J., Akroyd, J. and Kraft, M., 2021. The role of oxygenated species in the growth of graphene, fullerenes and carbonaceous particles. Carbon, 182, pp.203-213.

Martin, J.W., Salamanca, M. and Kraft, M., 2022. Soot inception: Carbonaceous nanoparticle formation in flames. Progress in Energy and Combustion Science, 88, p.100956.

Stevenson, S., 2021. Preparation, Extraction/Isolation from Soot, and Solubility of Fullerenes. In Handbook of Fullerene Science and Technology (pp. 1-25). Singapore: Springer Singapore.

Asadian, E., Ghalkhani, M. and Shahrokhian, S., 2019. Electrochemical sensing based on carbon nanoparticles: A review. Sensors and Actuators B: Chemical, 293, pp.183-209.

Kalhor, H.R. and Yahyazadeh, A., 2019. Investigating the effects of amino acid-based surface modification of carbon nanoparticles on the kinetics of insulin amyloid formation. Colloids and Surfaces B: Biointerfaces, 176, pp.471-479.