Mechanism of carbon nanotubes unzipping into graphene ribbons

Abstract

The fabrication of graphene nanoribbons from carbon nanotubes (CNTs) treated with potassium permanganate in a concentrated sulfuric acid solution has been reported by Kosynkin et al. [Nature (London) 458, 872 (2009)]. Here we report ab initio density functional theory calculations of such unzipping process. We find that the unzipping starts with the potassium permanganate attacking one of the internal C–C bonds of the CNT, stretching and breaking it. The created defect weakens neighboring bonds along the length of the CNT, making them energetically prone to be attacked too.

Chemical-free graphene by unzipping carbon nanotubes using cryo-milling

“…In this paper we present a method of producing chemicalfree graphene from CNTs. The anisotropic nature of CNT gives rise to a complex deformation and fracturing process [20][21][22][23]. In such kind of complex processes, the fracturing of C-C bonds along a particular direction needs high energy, which can be provided using high strain rate (10 8À10 /s) deformation [20][21][22][23].…”

Electrochemical behavior of hybrid carbon nanomaterials: the chemistry behind electrochemistry

“…The first step is the formation of manganate ester as the rate-determining step. Pairs of oxygen atoms from the permanganate anion bind and break the internal C-C bonds in the CNT, the stretching of the bonds involved in the first attack weakens the neighbor parallel bonds making them more vulnerable for the next oxygen pair attack, which takes place longitudinally along the CNT [40]. After initial manganate ester formation, the vicinal diols that are formed will eventually cleave at the carbon-carbon bond between them giving dione and further oxidation of ketones to carboxylic acids takes place [17].…”

Ab‐initio modeling of carbon nanotubes functionalized with pyrrolidine

“…One of the production processes is the cutting of carbon nanotubes along its axis. The opening or unzipping of carbon nanotubes via oxidative cutting has been observed [1] and simulated [2].…”