Carbon is one of the most abundant elements in nature. It is encountered widely in our daily lives in its various forms and compounds, such as graphite, diamond, hydrocarbons, fibres, soot, oil, complex molecules, Etc. (Terrones, Terrones et al., 2003). Carbon nanotubes (CNTs) are eminent members of the nanomaterial family(Faizan, Hussain et al. 2021).

Where will the technology make a difference?

Following the discovery of fullerenes (carbon nanocages) and the identification of carbon nanotubes (rolled graphene sheets) with novel nanostructures, it is expected that numerous technological applications will arise using such fascinating structures(Terrones, Terrones et al. 2003). Various technological applications are likely to arise using nanotubes for the fabrication of flat panel displays, gas storage devices, toxic gas sensors, Li+ batteries, robust and lightweight composites, conducting paints, electronic nanodevices, etc. (Terrones, 2003).

If high-energy-density lithium-oxygen battery (LOB) technology contributes to addressing climate change, improvements to LOB performance must not come at the cost of disproportionate increases in global warming potential (GWP) or cumulative energy demand (CED) over their lifecycle(Falinski, Albalghiti et al. 2021). Practical tests confirmed the possibility of using the proposed air heater using single-wall carbon nanotubes (SWCNT) and paraffin wax to work in Iraqi weather conditions (Habib, Ali et al. 2021).

Application of carbon nanotubes

Image 1: Source: https://www.newscientist.com/article/2093356-carbon-nanotubes-too-weak-to-get-a-space-elevator-off-the-ground/

Carbon Nanotube Applications

  • In electronics and electricity (Terrones, 2003)
  • Nanotube based-lamps are relatively cheap to manufacture and have exhibited lifetimes of 8000 h and high efficiency superior to that for the green (phosphorous) light bulbs.
  • Potential as building blocks for stable and intense field emission sources, thus opening new avenues in vacuum microelectronics.
  • Li+ batteries (using graphitic carbon in the anode) are the best energy storage instruments for assisting portable electronic devices. Nanofibers contribute to higher battery energy storage owing to an increase in cycle characteristics.
  • Supercapacitors can be used to provide fast acceleration and store braking energy electrically for hybrid electric vehicles.
  • Nanotubes could be the best material for storing hydrogen,
  • CNTs could be used in high-performance electronic devices
  • Because of their exceptional physical, chemical, and mechanical properties, Carbon nanotubes (CNTs) are demonstrated to be efficacious means in the plant science field, and various studies have shown the capability of CNTs to cross diverse plant cell blockades with the evaluation of the harmful effects of these nanomaterials(Faizan, Hussain et al. 2021).
  • For example, carbon nanotube (CNT) sponges are excellent in removing oleophilic contaminants; however, due to their super-hydrophobic nature, they are not as efficient when absorbing water-soluble substances(Camilli, Capista et al. 2022).
  • Few walls carbon nanotubes (FWCNTs), and multi-wall carbon nanotubes (MWCNTs) are being produced from plastic feed stock. The MWCNTs then undergo functionalization with the insertion of an oxygen functional group using the thermal method to produce functionalized multi-wall carbon nanotubes (FMWCNTs). These synthesized materials are characterized using Nitrogen Isotherm Adsorption Brunauer-Emmett-Teller (BET) surface area analysis, Raman Spectroscopy, X-Ray Photoelectron (XPS) analysis and Field Emission Scanning Electron Microscope (FESEM) and X-Ray Diffraction (XRD). Their performance on supercapacitors is also assessed using a galvanostatic charge-discharge analyzer (GCD)(Zhuang, 2022).

Advancement in Carbon Research

Because of their remarkable electronic and mechanical properties, carbon nanotubes are unique and exciting (Terrones, 2003), and nanocarbons will be crucial for the development of emerging technologies in the following years(Terrones, Terrones et al. 2003). The latter achievements show a clear advance in the use of nanotubes in current technologies, and it is clear that in the near future, further and unimaginable advances will be accomplished(Terrones, 2003). Individual CNT morphologies’ structures and the CNT molten carbonate growth mechanisms are explored using SEM (scanning electron microscopy), TEM (transmission electron microscopy), HAADF (high angle annular dark field), EDX (dispersive energy X-ray), X-ray diffraction), and Raman methods which could be used for nanofiltration and neural nets and demonstrated pores sizes ranging from 50 nm to 1 µm (Liu, Licht et al. 2022).

The hydrovolcanic effect, which is a voltage generated at the interface of water with polarizable materials, is an exciting new frontier for environmentally friendly electrical power generation(Kumar, Tabrizizadeh et al. 2022).

Recent investigations have revealed CNTs to be chemically captured into plant tracheary elements and thus have the possible use of these distinctive nanomaterials in crop management(Faizan, Hussain et al. 2021).

The single wall carbon nanotubes (SWCNT) /paraffin nanocomposite thermophysical properties were examined to show its effect on the solar air heater performance, and SWCNT/paraffin nanocomposite has improved the stored thermal energy by 20.7% for natural convection, and by 21.2% for forced convection compared to pure paraffin(Habib, Ali et al. 2021).

By means of a scalable method consisting of simply treating CNT sponges at mild temperatures in the air, we attach oxygen-containing functional groups to the CNT surface. The functionalized sponge becomes hydrophilic while preserving its micro- and macro-structure and can therefore be used to successfully remove toxic contaminants, such as pesticides, that are dissolved in water. This discovery expands the current range of applications of CNT sponges to those fields in which a hydrophilic character of the sponge is more suitable(Camilli, Capita et al. 2022).

It has been evaluated the performance of in-house synthesized multi-wall carbon nanotubes from plastic as electrode materials for supercapacitor applications and concluded that waste plastic is being recycled to produce better performing electrodes for supercapacitors, which is one of the answers to tackle the world energy crisis, climate change and plastic pollution(Zhuang, 2022).

Climate Change and Carbon nanotubes

CO2 is the main cause of anthropogenic global warming, and its utilization and transformation into a stable, valuable material provide an incentivized pathway to mitigate climate change(Liu, Licht et al. 2022). Climate change mitigation efforts will require a portfolio of solutions, including improvements to energy storage technologies in electric vehicles and renewable energy sources, such as the high-energy-density lithium-oxygen battery (LOB)(Falinski, Albalghiti et al. 2021). The resultant devices made from high strength, highly flexible, lightweight, thermally and chemically stable, surface functionalized multi-walled carbon nanotube (FMWCNT), supported on a polyethene terephthalate (PET) material, provide a myriad of benefits, including high power generation (210 μW g−1) even under high humidity, making it less prone to damage or environmental degradation during long-term exposure(Kumar, Tabrizizadeh et al. 2022).

Increasing shreds of evidence reveal that the augmentation of nanoparticles to plants can notably reduce detrimental effects caused by several severe environmental conditions and, therefore, modulate several mechanisms in plants by using several types of nanoparticles and nano fertilizers(Faizan, Hussain et al. 2021).

Converting plastic waste to multi-wall carbon nanotubes (MWCNTs) produced from plastic feed stock as electrode materials for supercapacitor is highly feasible to replace the electrode in typical commercial carbon-based electrode supercapacitor(Zhuang, 2022).

Conspiracies

The principal commercial technology for carbon nanotube (CNT) production had been chemical vapour deposition, which is an order of magnitude more expensive, generally requires Metallo-organics rather than CO2 as reactants, and can be high energy and CO2 emission intensive (carries a high carbon positive, rather than negative, footprint)(Liu, Licht et al. 2022).

 

Further Readings

Camilli, L., et al. (2022). “Synthesis of hydrophilic carbon nanotube sponge via post-growth thermal treatment.”  33(24): 245707.

Faizan, M., et al. (2021). “Effect of Carbon Nanotubes on Abiotic Stress Response in Plants: An Overview.” 217-229.

Falinski, M. M., et al. (2021). “Performance and Sustainability Tradeoffs of Oxidized Carbon Nanotubes as a Cathodic Material in Lithium‐Oxygen Batteries.”  14(3): 898-908.

Habib, N. A., et al. (2021). “Carbon nanotubes/paraffin wax nanocomposite for improving the performance of a solar air heating system.”  23: 100877.

Kumar, R., et al. (2022). “Hydrovoltaic power generation from multi-walled carbon nanotubes.”  6(4): 1141-1147.

Liu, X., et al. (2022). “Controlled Transition Metal Nucleated Growth of Carbon Nanotubes by Molten Electrolysis of CO2.”  12(2): 137.

Terrones, M., et al. (2003). “The carbon nanocosmos: novel materials for the twenty-first century.”  361(1813): 2789-2806.

Terrones, M. J. A. r. o. m. r. (2003). “Science and technology of the twenty-first century: synthesis, properties, and applications of carbon nanotubes.”  33(1): 419-501.

Zhuang, J. (2022). “Converting plastic waste into carbon nanotubes as electrode materials for supercapacitors application.”

(The feature image for this article was taken from: https://stock.adobe.com/ca/search?k=carbon+nanotubes&search_type=usertyped&asset_id=326883438)

Basudev Neupane

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