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'''Carbon nanofoam''' is an [[allotropes of carbon|allotrope of carbon]] discovered in 1997 by [[Andrei V. Rode]] and co-workers at the [[Australian National University]] in [[Canberra]].<ref name="Rode1999">{{cite journal |
'''Carbon nanofoam''' is an [[allotropes of carbon|allotrope of carbon]] discovered in 1997 by [[Andrei V. Rode]] and co-workers at the [[Australian National University]] in [[Canberra]].<ref name="Rode1999">{{cite journal|last=Rode|first=A.V.|author2=Hyde, S.T. |author3=Gamaly, E.G. |author4=Elliman, R.G. |author5=McKenzie, D.R. |author6= Bulcock, S. |title=Structural analysis of a carbon foam formed by high pulse-rate laser ablation|journal=Applied Physics A: Materials Science & Processing|year=1999|volume=69|issue=7|pages=S755–S758|doi=10.1007/s003390051522|bibcode=1999ApPhA..69S.755R|s2cid=96050247}}</ref> It consists of a cluster-assembly of carbon atoms strung together in a loose three-dimensional web. The [[fractal]]-like bond structure consists of sp<sup>2</sup> [[graphite]]-like clusters connected by sp<sup>3</sup> bonds. The sp<sup>3</sup> bonds are located mostly on the surface of the structure and make up 15% to 45% of the material, making its framework similar to [[diamond-like carbon]] films.<ref name=":1">{{Cite journal|last1=Rode|first1=A.V.|last2=Gamaly|first2=E.G.|last3=Luther-Davies|first3=B.|date=2000-02-01|title=Formation of cluster-assembled carbon nano-foam by high-repetition-rate laser ablation|journal=Applied Physics A|language=en|volume=70|issue=2|pages=135–144|doi=10.1007/s003390050025|issn=1432-0630|bibcode=2000ApPhA..70..135R|hdl=1885/35128|s2cid=98408906|hdl-access=free}}</ref> The material is remarkably light, with a density of 2-10 x 10<sup>−3</sup> g/cm<sup>3</sup> (0.0012 lb/ft<sup>3</sup>) and is similar to an [[aerogel]].<ref name="Rode1999"/><ref>{{cite journal|last=Zani|first=A.|author2=Dellasega, D. |author3=Russo, V. |author4= Passoni, M. |title=Ultra-low density carbon foams produced by pulsed laser deposition|journal=Carbon|volume=56|pages=358–365|doi=10.1016/j.carbon.2013.01.029|year=2013}}</ref> Other remarkable physical properties include the large surface area of 300–400 m<sup>2</sup>/g (similar to [[zeolite]]s).<ref name=":2">{{Cite journal|last1=Blinc|first1=R.|last2=Arčon|first2=D.|last3=Umek|first3=P.|last4=Apih|first4=T.|last5=Milia|first5=F.|last6=Rode|first6=A. V.|date=2007|title=Carbon nanofoam as a potential hydrogen storage material|journal=Physica Status Solidi B|language=en|volume=244|issue=11|pages=4308–4310|doi=10.1002/pssb.200776149|issn=1521-3951|bibcode=2007PSSBR.244.4308B}}</ref> {{convert|1|USgal}} of nanofoam weighs about {{convert|0.25|oz}}.<ref>{{cite news |author=Kenneth Chang |title=A Flaky New Carbon: It's Feather Light and Magnetic |url=https://www.nytimes.com/2004/04/06/science/a-flaky-new-carbon-it-s-feather-light-and-magnetic.html |newspaper=[[The New York Times]] |date=April 6, 2004 }}</ref> |
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Each cluster is about 6 nanometers wide and consists of about 4000 carbon [[atom]]s linked in [[graphite]]-like sheets that are given negative curvature by the inclusion of [[heptagon]]s among the regular [[hexagon]]al pattern. This is the opposite of what happens in the case of [[buckminsterfullerene]]s |
Each cluster is about 6 nanometers wide and consists of about 4000 carbon [[atom]]s linked in [[graphite]]-like sheets that are given negative curvature by the inclusion of [[heptagon]]s among the regular [[hexagon]]al pattern. This is the opposite of what happens in the case of [[buckminsterfullerene]]s in which carbon sheets are given positive curvature by the inclusion of [[pentagon]]s. |
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The large-scale structure of carbon nanofoam is similar to that of an [[aerogel]], but with 1% of the density of previously produced [[aerogel#Carbon|carbon aerogels]]—or only a few times the density of [[air]] at [[sea level]]. Unlike carbon |
The large-scale structure of carbon nanofoam is similar to that of an [[aerogel]], but with 1% of the density of previously produced [[aerogel#Carbon|carbon aerogels]]—or only a few times the density of [[air]] at [[sea level]]. Unlike [[carbon aerogel]]s, carbon nanofoam is a poor [[electrical conductivity|electrical conductor]]. The nanofoam contains numerous [[unpaired electron]]s, which Rode and colleagues propose is due to carbon atoms with only three bonds that are found at topological and bonding defects. This gives rise to what is perhaps carbon nanofoam's most unusual feature: it is attracted to magnets, and [[Curie point|below −183 °C]] can itself be made magnetic. |
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Carbon nanofoam is the only form of pure carbon known to be [[ferromagnetic]] which is unusual for a carbon allotrope.<ref name=":0">{{Cite journal|last1=Rode|first1=A. V.|last2=Gamaly|first2=E. G.|last3=Christy|first3=A. G.|last4=Fitz Gerald|first4=J. G.|last5=Hyde|first5=S. T.|last6=Elliman|first6=R. G.|last7=Luther-Davies|first7=B.|last8=Veinger|first8=A. I.|last9=Androulakis|first9=J.|last10=Giapintzakis|first10=J.|date=2004-08-17|title=Unconventional magnetism in all-carbon nanofoam|journal=Physical Review B|volume=70|issue=5|pages=054407|doi=10.1103/PhysRevB.70.054407|bibcode=2004PhRvB..70e4407R|arxiv=cond-mat/0310751|s2cid=4011768}}</ref> Ferromagnetism is an intrinsic property observed in the carbon nanofoam and may be accounted for by its complex structure. Impurities in the material are excluded as the source of magnetism as they are not sufficient for the strong magnetization observed. Researchers postulate that embedded carbon atoms with unpaired electrons carry enough of a [[magnetic moment]] to lead to strong magnetization.<ref name=":0" /> The sheet curvature localizes unpaired electrons by breaking up the [[Pi bond|π-electron]] clouds and sterically protects the electrons which normally would be too reactive to persist. The ferromagnetism of the carbon nanofoam is sensitive to time and temperature. Some magnetism is lost within the first few hours of synthesis, however most of it is persistent.<ref name=":0" /> Carbon nanofoam may have some application in [[spintronic]] devices which exploits electron spin as a further [[degrees of freedom (physics and chemistry)|degree of freedom]]. |
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Carbon nanofoam may be suitable for hydrogen storage due to its low density and high surface area. Preliminary experimentation has shown that hydrogen can be stored in the nanofoam at room temperature in a reversible process.<ref name=":2" /> |
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==Synthesis == |
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Carbon nanofoam clusters can be synthesized through high-repetition-rate [[laser ablation]] in inert gases such as [[argon]]. Short ([[Femtosecond|fs]]), low-energy (μJ) pulses delivered at high rates of repetition (10 kHz – 100 MHz) generate carbon vapors for deposition.<ref name=":1" /> Ambient gas is heated from room temperature with the atomized carbon which leads to an increase in the partial density of the carbon in the chamber. In optimal conditions, the inert gas does not cool down but maintains its high temperature between cycles of formation. Subsequent cycles in the chamber are carried out at temperatures above the formation threshold temperature initiating sp<sup>2</sup> bonding. The increase in density and temperature promotes favorable conditions for the formation of carbonaceous clusters. The rate of consumption exceeds the rate of evaporation by laser ablation and thus the formation is in a non-equilibrium state. |
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==See also== |
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*[[Truncated order-7 triangular tiling]] |
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==References== |
==References== |
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{{Reflist}} |
{{Reflist}} |
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==Further reading== |
==Further reading== |
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{{expert-subject|reason=This section is excessively long given the short length of the article. An expert is needed to whittle down this list to something more digestible.|date = July 2015}} |
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{{refbegin|2}} |
{{refbegin|2}} |
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*{{cite journal | last = Rode | first = A. V. | |
*{{cite journal | last = Rode | first = A. V. |author2=Gamaly, E. G. |author3=Luther-Davies, B. | year = 2000 | title = Formation of cluster-assembled carbon nano-foam by high-repetition-rate laser ablation | journal = Applied Physics A: Materials Science & Processing | volume = 70 | issue = 2 | pages = 135–144 | doi = 10.1007/s003390050025 |bibcode = 2000ApPhA..70..135R }} |
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*Rode, Andrei; Gamaly, Eugene; Luther-Davies, Barry. "Method for deposition of thin films", International Patent Application No. PCT/AU98/00739, priority date 11 September |
*Rode, Andrei; Gamaly, Eugene; Luther-Davies, Barry. "Method for deposition of thin films", International Patent Application No. PCT/AU98/00739, priority date 11 September 1997; "Method of deposition of thin films of amorphous and crystalline microstructures based on ultrafast pulsed laser deposition", {{patent|US|6312760}} (2001). |
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*{{cite journal | last = Rode | first = A. V. |
*{{cite journal | last = Rode | first = A. V. | year = 2002 | title = Electronic and magnetic properties of carbon nanofoam produced by high-repetition-rate laser ablation | journal = Applied Surface Science | volume = 197–198 | pages = 644–649 | doi = 10.1016/S0169-4332(02)00433-6 |bibcode = 2002ApSS..197..644R |display-authors=etal}} |
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*{{cite journal | last = Rode | first = A. V. |
*{{cite journal | last = Rode | first = A. V. | year = 2004 | title = Unconventional magnetism in all-carbon nanofoam | journal = Phys. Rev. B | volume = 70 | issue = 5| page = 054407 | doi = 10.1103/PhysRevB.70.054407 | url = http://laserspark.anu.edu.au/Pubs/rode_04_unconventional.pdf |arxiv = cond-mat/0310751 |bibcode = 2004PhRvB..70e4407R |display-authors=etal}} |
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*{{cite book |title=Encyclopaedia of Nanoscience and Nanotechnology |volume=7 |last=Gamaly |first=E. G. | |
*{{cite book |title=Encyclopaedia of Nanoscience and Nanotechnology |volume=7 |last=Gamaly |first=E. G. |author2=Rode, A. V. |editor=Nalwa, H. S. |year=2004 |publisher=American Scientific Publishers |location=Stevenson Range |pages=783–809 |chapter=Nanostructures created by lasers |chapter-url= http://laserspark.anu.edu.au/Pubs/gamaly_04_nanostructures.pdf }} |
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*{{cite journal | last = Rode | first = A. V. |
*{{cite journal | last = Rode | first = A. V. | year = 2005 | title = Strong paramagnetism and possible ferromagnetism in pure carbon nanofoam produced by laser ablation | journal = Journal of Magnetism and Magnetic Materials | volume = 290–291 | issue = 1 | pages = 298–301 | doi = 10.1016/j.jmmm.2004.11.213 | url = http://laserspark.anu.edu.au/Pubs/rode_05_strong.pdf |bibcode = 2005JMMM..290..298R |display-authors=etal}} |
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*{{cite journal | last = Arčon | first = D. |
*{{cite journal | last = Arčon | first = D. | year = 2006 | title = Origin of Magnetic Moments in Carbon Nanofoam | journal = Phys. Rev. B | volume = 74 | issue = 1| page = 014438 | doi = 10.1103/PhysRevB.74.014438 | url = http://laserspark.anu.edu.au/Pubs/arcon_06_origin.pdf |bibcode = 2006PhRvB..74a4438A |display-authors=etal}} |
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*{{cite journal | last = Blinc | first = R. |
*{{cite journal | last = Blinc | first = R. | year = 2006 | title = <sup>13</sup>C NMR and EPR of carbon nanofoam | journal = Physica Status Solidi B | volume = 243 | issue = 13 | pages = 3069–3072 | doi = 10.1002/pssb.200669152 | url = http://laserspark.anu.edu.au/Pubs/blinc_06_13c.pdf |bibcode = 2006PSSBR.243.3069B |display-authors=etal}} |
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*{{cite book |title=Carbon-based magnetism: an overview of the magnetism of metal free carbon-based compounds and materials |last=Rode |first=A. V. |
*{{cite book |title=Carbon-based magnetism: an overview of the magnetism of metal free carbon-based compounds and materials |last=Rode |first=A. V. |editor=Makarova, Tatiana L. |editor2=Palacio, Fernando |year=2006 |publisher=Elsevier |location=Amsterdam |isbn=0-444-51947-5 |pages=463–482 |chapter=Magnetic properties of novel carbon allotropes | url = http://laserspark.anu.edu.au/Pubs/rode_06_magnetic.pdf|display-authors=etal}} |
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*{{cite journal | last = Lau | first = D. W. M. |
*{{cite journal | last = Lau | first = D. W. M. | year = 2007 | title = High-Temperature Formation of Carbon Onions within Nanofoam: An Experimental and Simulation Study | journal = Phys. Rev. B | volume = 75 | issue = 23| page = 233408 | doi = 10.1103/PhysRevB.75.233408 | url = http://laserspark.anu.edu.au/Pubs/lau_07_high.pdf |bibcode = 2007PhRvB..75w3408L |display-authors=etal}} |
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{{refend}} |
{{refend}} |
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{{Allotropes of carbon}} |
{{Allotropes of carbon}} |
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{{DEFAULTSORT:Carbon Nanofoam}} |
{{DEFAULTSORT:Carbon Nanofoam}} |
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[[Category: |
[[Category:Allotropes of carbon]] |
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[[Category: |
[[Category:Group IV semiconductors]] |
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[[Category:Nanomaterials]] |
[[Category:Nanomaterials]] |
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[[Category:Foams]] |
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Latest revision as of 08:50, 26 May 2024
Carbon nanofoam is an allotrope of carbon discovered in 1997 by Andrei V. Rode and co-workers at the Australian National University in Canberra.[1] It consists of a cluster-assembly of carbon atoms strung together in a loose three-dimensional web. The fractal-like bond structure consists of sp2 graphite-like clusters connected by sp3 bonds. The sp3 bonds are located mostly on the surface of the structure and make up 15% to 45% of the material, making its framework similar to diamond-like carbon films.[2] The material is remarkably light, with a density of 2-10 x 10−3 g/cm3 (0.0012 lb/ft3) and is similar to an aerogel.[1][3] Other remarkable physical properties include the large surface area of 300–400 m2/g (similar to zeolites).[4] 1 US gallon (3.8 L; 0.83 imp gal) of nanofoam weighs about 0.25 ounces (7.1 g).[5]
Each cluster is about 6 nanometers wide and consists of about 4000 carbon atoms linked in graphite-like sheets that are given negative curvature by the inclusion of heptagons among the regular hexagonal pattern. This is the opposite of what happens in the case of buckminsterfullerenes in which carbon sheets are given positive curvature by the inclusion of pentagons.
The large-scale structure of carbon nanofoam is similar to that of an aerogel, but with 1% of the density of previously produced carbon aerogels—or only a few times the density of air at sea level. Unlike carbon aerogels, carbon nanofoam is a poor electrical conductor. The nanofoam contains numerous unpaired electrons, which Rode and colleagues propose is due to carbon atoms with only three bonds that are found at topological and bonding defects. This gives rise to what is perhaps carbon nanofoam's most unusual feature: it is attracted to magnets, and below −183 °C can itself be made magnetic.
Carbon nanofoam is the only form of pure carbon known to be ferromagnetic which is unusual for a carbon allotrope.[6] Ferromagnetism is an intrinsic property observed in the carbon nanofoam and may be accounted for by its complex structure. Impurities in the material are excluded as the source of magnetism as they are not sufficient for the strong magnetization observed. Researchers postulate that embedded carbon atoms with unpaired electrons carry enough of a magnetic moment to lead to strong magnetization.[6] The sheet curvature localizes unpaired electrons by breaking up the π-electron clouds and sterically protects the electrons which normally would be too reactive to persist. The ferromagnetism of the carbon nanofoam is sensitive to time and temperature. Some magnetism is lost within the first few hours of synthesis, however most of it is persistent.[6] Carbon nanofoam may have some application in spintronic devices which exploits electron spin as a further degree of freedom.
Carbon nanofoam may be suitable for hydrogen storage due to its low density and high surface area. Preliminary experimentation has shown that hydrogen can be stored in the nanofoam at room temperature in a reversible process.[4]
Synthesis
[edit]Carbon nanofoam clusters can be synthesized through high-repetition-rate laser ablation in inert gases such as argon. Short (fs), low-energy (μJ) pulses delivered at high rates of repetition (10 kHz – 100 MHz) generate carbon vapors for deposition.[2] Ambient gas is heated from room temperature with the atomized carbon which leads to an increase in the partial density of the carbon in the chamber. In optimal conditions, the inert gas does not cool down but maintains its high temperature between cycles of formation. Subsequent cycles in the chamber are carried out at temperatures above the formation threshold temperature initiating sp2 bonding. The increase in density and temperature promotes favorable conditions for the formation of carbonaceous clusters. The rate of consumption exceeds the rate of evaporation by laser ablation and thus the formation is in a non-equilibrium state.
See also
[edit]References
[edit]- ^ a b Rode, A.V.; Hyde, S.T.; Gamaly, E.G.; Elliman, R.G.; McKenzie, D.R.; Bulcock, S. (1999). "Structural analysis of a carbon foam formed by high pulse-rate laser ablation". Applied Physics A: Materials Science & Processing. 69 (7): S755–S758. Bibcode:1999ApPhA..69S.755R. doi:10.1007/s003390051522. S2CID 96050247.
- ^ a b Rode, A.V.; Gamaly, E.G.; Luther-Davies, B. (2000-02-01). "Formation of cluster-assembled carbon nano-foam by high-repetition-rate laser ablation". Applied Physics A. 70 (2): 135–144. Bibcode:2000ApPhA..70..135R. doi:10.1007/s003390050025. hdl:1885/35128. ISSN 1432-0630. S2CID 98408906.
- ^ Zani, A.; Dellasega, D.; Russo, V.; Passoni, M. (2013). "Ultra-low density carbon foams produced by pulsed laser deposition". Carbon. 56: 358–365. doi:10.1016/j.carbon.2013.01.029.
- ^ a b Blinc, R.; Arčon, D.; Umek, P.; Apih, T.; Milia, F.; Rode, A. V. (2007). "Carbon nanofoam as a potential hydrogen storage material". Physica Status Solidi B. 244 (11): 4308–4310. Bibcode:2007PSSBR.244.4308B. doi:10.1002/pssb.200776149. ISSN 1521-3951.
- ^ Kenneth Chang (April 6, 2004). "A Flaky New Carbon: It's Feather Light and Magnetic". The New York Times.
- ^ a b c Rode, A. V.; Gamaly, E. G.; Christy, A. G.; Fitz Gerald, J. G.; Hyde, S. T.; Elliman, R. G.; Luther-Davies, B.; Veinger, A. I.; Androulakis, J.; Giapintzakis, J. (2004-08-17). "Unconventional magnetism in all-carbon nanofoam". Physical Review B. 70 (5): 054407. arXiv:cond-mat/0310751. Bibcode:2004PhRvB..70e4407R. doi:10.1103/PhysRevB.70.054407. S2CID 4011768.