Structural systematics in boron-doped single wall carbon nanotubes

Abstract

We report atomic level high resolution transmission electron microscopy (HRTEM), electron nanodiffraction and nano-electron energy loss spectroscopy (nano-EELS) of boron-doped carbon nanostructures obtained by laser ablation of Co/Ni/B-doped carbon targets. The observations provide direct evidence for structural systematics and atomic structural defects as a function of the B content in the target. Targets with low B concentration (below 3 at%), produced ropes of single wall carbon nanotubes (SWCNTs) with no detectable boron present in the SWCNT ropes. However, unintended N-doping of the curved honeycomb lattice was observed in the 2.5 at% B sample (which is attributed to the possible presence of small amounts of N in the targets or reaction environments), with striking consequences for doping of heteroatoms within the hexagonal lattice of the graphene layer. At higher B concentration (3.5 at% and higher), there are significant changes in the nanostructure, which exhibits defective graphite layers and a small number of double wall carbon nanotubes (DWCNTs). At the higher B concentration, boron-doping is evidenced in the form of very small amorphous B clusters trapped in graphite-like defective sites.

First-principles study on the enhancement of lithium storage capacity in boron doped graphene

“…The maximum capacity of CNTs can be increased to as high as 1000 mAh/g ͑in the form of Li 2.7 C 6 ͒ by chemical etching 4 or ball-milling, 5 which open up paths allowing Li ions to diffuse inside the CNTs. Ever since boron doped CNTs with different B versus C ratios have been synthesized, [6][7][8] they have been expected to have higher Liion storage capability than pristine CNTs, and this has been confirmed both experimentally 9 and theoretically. 10 Additionally, boron doped carbonaceous materials have exhibited higher reversible capacity and better cycling stability than their pure counterparts.…”

The synthesis of carbon nanomaterials using chlorinated hydrocarbons over a Fe-Co/CaCO3 catalyst

“…Modification of CNTs has thus led to the creation of new functional and construction materials. 11 Doping of the carbonaceous materials with non-carbon atoms, such as nitrogen, [12][13][14][15][16][17][18][19] boron, [20][21][22][23][24] sulphur, [25][26][27][28][29] oxygen [30][31][32][33][34][35][36] and halogens 11,[37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55] has been explored over the past two decades. Modification of the carbon surface and electronic properties has also been explored but the effect of chlorine (Cl) on the morphology of carbon nanomaterials is not well established.…”

Properties of Carbon Nanotubes under External Factors

“…4c). It has been considered that the common doping atoms in carbon nanotubes are boron and nitrogen, which can appear during laser-ablation and arcdischarge synthesizing processes or during substitutional reaction methods (Droppa et al, 2002;Gai et al, 2004;Golberg et al, 1999). Since B and N atomic radii have similar size to the C atom, they create a small perturbation in the nanotube structure in comparison to the perfect one.…”