Home
This Title All WIREs
WIREs RSS Feed
How to cite this WIREs title:
WIREs Comput Mol Sci
Impact Factor: 8.836

Isomerization of sp 2 ‐hybridized carbon nanomaterials: structural transformation and topological defects of fullerene, carbon nanotube, and graphene

Full article on Wiley Online Library:   HTML PDF

Can't access this content? Tell your librarian.

The structural transformation of various carbon nanomaterials, such as fullerene, carbon nanotube (CNT), and graphene, has been extensively studied both experimentally and theoretically. It was broadly recognized that the isomerization of the sp2‐hybridized carbon network through the generalized Stone–Wales transformation (GSWT), which is equivalent to a CC bond's in‐plane rotation, is the key mechanism facilitating most structural revolutions in carbon materials. The GSWT process also plays a crucial role in the shape change, defect healing and the growth in these carbon materials and may greatly affect their mechanical, chemical, and electronic performances. In this review, we summarize the previous studies on the GSWT and topological defects in the sp2 carbon network as well as the consequent results of sp2‐hybridized carbon materials’ isomerization, including structural shrinkage of the giant fullerenes and CNTs at high temperature, plastic deformation of CNTs, coalescence of the fullerenes and carbon peapods, topological defects evolution under high energetic irradiation, and healing of the defects during the chemical vapor deposition growth of CNT and graphene. This review provides a clear picture of the isomerization of the sp2‐hybridized carbon materials, from single step process until the large‐scale structural transformation, and many examples for the readers to get into the topic deeply step by step. WIREs Comput Mol Sci 2017, 7:e1283. doi: 10.1002/wcms.1283

This article is categorized under:

  • Structure and Mechanism > Reaction Mechanisms and Catalysis
  • Structure and Mechanism > Computational Materials Science
(a) A cross‐section image and (b) a side view image of the carbon peapod. (Reprinted by permission from Ref . Copyright 1998 Macmillan Publishers Ltd) (c) Real peapod. (d) HRTEM images of carbon peapods and the peapod derived inner tubes at the temperature of 1250°C. (Reprinted with permission from Ref . Copyright 2007 American Chemical Society)
[ Normal View | Magnified View ]
(a) Two contrasting modes of CNT failure under axial strain: brittle cleavage (blue arrow) with the direct breakage of longitudinal CC bonds (blue) at low temperature and ductile (plastic) yield (red arrow) via the flipping of the circumferential CC bonds (red) at high temperature. (Reprinted with permission from Ref . Copyright 2006 National Academy of Sciences) (b, c) Snapshots of the formation of an SW defects in a SWNT with 10% strain at T = 2000 K and the plastic flow after 2.5 ns at T = 3000 K with 3% strain taken during the large‐scale MD simulation. (Reprinted with permission from Ref . Copyright 1998 American Physical Society) (d) The movement of 5|7 cores is determined by balance of three driving forces: Fs is produced by applied tensile stress, Fchem is produced by the reduction of free energy of carbon as it sublimates into gas phase. fc is produced by the reduction in the internal elastic energy caused by the tube thickening or thinning. (e) The 5|7 core continues shuttling back and forth by sequence removing of the carbon atoms from the SWNT wall. (Reprinted with permission from Ref . Copyright 2007 American Physical Society)
[ Normal View | Magnified View ]
(a) Energy cost of removing a C2 or C1 unit from different sites in the fullerene C320. (b, c) Formation of pentagon plus pentagon–heptagon pair (5 + 5|7) is created after the removal of a C2 unit near a pentagon in the fullerene. (d, e) When the extra 5|7 approaches to a pentagon by gliding, removal of a C2 unit annihilates the 5|7. (f, g) A Stone–Wales (SW) bond flip may annihilate a 5|7 in the vicinity of a pentagon, and the reverse process creates an additional 5|7. (h) Two kinetic processes from C2 removal from a fullerene until the lattice perfection restoration. (i) The simulated shrinkage from a giant fullerene (C720) to a tiny fullerene (C20). (Reprinted with permission from Ref . Copyright 2007 American Physical Society) (j) A 5|7 in the carbon nanotube wall serve as the source of C2 removal and it shuttles forth and back along the tube wall at 20 and 55% mass lose, respectively. (Reprinted with permission from Ref . Copyright 2007 American Chemical Society)
[ Normal View | Magnified View ]
A series generalized Stone–Wales (SW) transformation steps in a perfect hexagonal graphitic lattice. A randomly selected CC bond (a) rotated by 90° rotation creates a standard SW defect. (b) The continuous rotations of a shoulder CC bond of a 5|7 (enclosed by the dotted yellow circles in (b) and (c) of the SW defect splits the SW defect into two 5|7s and reorganizes all the CC bonds between them (b → c → d). The reorganized sp2 networks between the two separated 5|7s are marked in yellow.
[ Normal View | Magnified View ]
(a) The isomerization from a Ih –C60 to a C 2v–C60 requires a CC bond rotation or an SW transformation in the sp2 network of the fullerene. The activation energy of such a transition is ~7 eV and the final structure is 1.6 eV higher than the initial one. (Reprinted with permission from Ref . Copyright 2011 American Physical Society) (b) The energy barrier of such a transformation can be greatly reduced with the presence of a tungsten atom at the vicinity of the rotated CC bond. (Reprinted with permission from Ref . Copyright 2008 American Physical Society)
[ Normal View | Magnified View ]
(a) Schematic model and (b) HRTEM images of SW defect in the graphene. (Reprinted with permission from Ref . Copyright 2008 American Chemical Society)
[ Normal View | Magnified View ]
(a, b) Nanocone (nanopringle) produced by introducing only a pentagon (heptagon) into a perfect sp2 network. (Reprinted with permission from Ref . Copyright 2010 American Chemical Society) (c) A 5|7 pair in a sp2 network can be viewed as an edge dislocation with a burgers vector b . (Reprinted with permission from Ref . Copyright 2007 American Physical Society) (d) A 5|7 pair in carbon nanotube wall changes its chirality. (e) Intratube junction formed by a series 5|7s in a straight CNT wall. (Reprinted with permission from Ref . Copyright 2011 Royal Society of Chemistry) and a grain boundary of graphene (f) composed of head‐to‐tail arranged 5|7 pairs. (Reprinted with permission from Ref . Copyright 2011 Macmillan Publishers Ltd)
[ Normal View | Magnified View ]
Single vacancy (a) before and (b) after reconstruction. Divacancy (c) before and (d) after reconstruction.
[ Normal View | Magnified View ]
(a) Direct coalescence of the C60 + C60 to spherical C120. (b) Transformation of a nanodiamond structure into a large fullerene. (Reprinted with permission from Ref . Copyright 2014 American Chemical Society)
[ Normal View | Magnified View ]
(a) A fraction model of CNT–metal interface modeled as a graphene on the Ni (111) face with the armchair edge attached to a metal step (b). (c–e) The healing processes (from left to right: original, transitional, and final states) of the pentagon, heptagon, and 5|7 pair at the edges of the open ends of the grown CNT, respectively. (f) The energy barrier (E*) (black real line with symbols) and the reaction energy (Ea ) (red dashed line with symbols) for the defects healing of pentagons, heptagon, and 5|7 pairs on stepped Fe(111)/Co(111)/Ni(111) surfaces. (Reprinted with permission from Ref . Copyright 2012 American Physical Society) (g) Healing of metal atoms embedded at the kink of the zigzag edges of the graphene on Cu(111) surface. (Reprinted with permission from Ref . Copyright 2013 American Chemical Society)
[ Normal View | Magnified View ]
(a) The reconstruction of the a divacany (V2) in the graphene under electron irradiation and found that the evolution of the V2(5|8|5) to the V2(r66). (b–p) Evolutions of the multiple vacancies into larger defects with more complex structures. (Reprinted with permission from Refs and . Copyright 2014, 2015 Royal Society of Chemistry)
[ Normal View | Magnified View ]
Reconstructions of the defects under irradiation. (a) Stone–Wales defect, (b) defect‐free graphene, (c) V1(5–9) single vacancy, (d) V2(5–8–5) divacancy, (e) V2(555–777) divacancy, (f) V2(5555–6–7777) divacancy. (Reprinted with permission from Ref . Copyright 2011 American Physical Society) (g) Three linked divacancies. (h) A divacancy after a SW transformation. (i) Defects clustered around one of a pair of dislocations. (j) An enclosed, rotationally misaligned core of six hexagons, surrounded by a complete loop of pentagons and heptagons. (k) A larger, partially completed loop, isolating several rotated hexagons. (l) Two divacancy defects, each having been transformed via two SW rotations, leading to a single isolated, rotated hexagon. (Reprinted by permission from Ref . Copyright 2014 Macmillan Publishers Ltd) (m) A sequence of micrographs showing the disappearance of a flower defect under an electron irradiation during a 30‐s total exposure. (Reprinted with permission from Ref . Copyright 2012 American Chemical Society)
[ Normal View | Magnified View ]
(a)The healing of the topological defects, i.e., pentagon (pink), heptagon (yellow), 5|7 pairs (pink and yellow), and octagon (blue), at the open end of the SWNT by a sequence of GSW bond rotations during the EDKMC stage. For the sake of the clarity, nickel particle attached to the open end is removed artificially. (b) The pentagon with a dangling carbon atom attached is a key step for the formation of the hexagon during the incorporation of the carbon atoms to the carbon nanotube–metal interface. (c) A defect‐free SWNT with the length of ~4.5 nm is simulated. (Reprinted with permission from Ref . Copyright 2015 Royal Society of Chemistry) (d) The healing process of the pentagon with a dangling carbon atom on the graphene on Ni(111) surface. (e) The simulated graphene by pure MD at the temperature 1300 K. (Reprinted with permission from Ref . Copyright 2016 Royal Society of Chemistry)
[ Normal View | Magnified View ]
(a) Coalescence of encapsulated fullerenes (C60 + C60) in a (18,0) SWNT at the temperature of 2000 K with the energy drop of 13 eV. The chirality of the final inner tube is (6, 4). (b) Large chiral‐angle distribution of the inner tubes coalesced by the encapsulated fullerenes in the outer SWNT of (14,5), (10,10), (18,0), and (19,0), respectively. (c) Raman spectra of the inner tube by using the different laser excitation energies. Solid line: peapod‐derived double‐walled carbon nanotube (DWNT). Dashed line: high‐pressure carbon monoxide (HiPCO) processed SWNTs. (d) Relative photoluminescence (PL) intensity of the inner wall fused from the peapods at different temperatures of 1700°C, 1800°C, and 2000°C, respectively. The PL data were extracted from Ref . (Reprinted with permission from Ref . Copyright 2010 American Physical Society) (e) The continued coalescence of the two longer inner tubes (armchair + zigzag) with an stable intratube junction formed (f), which is composed of the loop of head‐to‐tail 5|7 pairs (pink polygons). (g, h) HRTEM images of the coalescence of two adjacent inner tubes and the formed intratube junction in the peapod‐grown DWNTs by thermal annealing at 1700°C, respectively. (Reprinted with permission from Ref . Copyright 2011 Royal Society of Chemistry)
[ Normal View | Magnified View ]

Browse by Topic

Structure and Mechanism > Reaction Mechanisms and Catalysis
Structure and Mechanism > Computational Materials Science

Access to this WIREs title is by subscription only.

Recommend to Your
Librarian Now!

The latest WIREs articles in your inbox

Sign Up for Article Alerts