Wall‐ and Hybridisation‐Selective Synthesis of Nitrogen‐Doped Double‐Walled Carbon Nanotubes

Abstract

Controlled nitrogen‐doping is a powerful methodology to modify the properties of carbon nanostructures and produce functional materials for electrocatalysis, energy conversion and storage, and sensing, among others. Herein, we report a wall‐ and hybridisation‐selective synthetic methodology to produce double‐walled carbon nanotubes with an inner tube doped exclusively with graphitic sp2‐nitrogen atoms. Our measurements shed light on the fundamental properties of nitrogen‐doped nanocarbons opening the door for developing their potential applications.

A Singular Molecule-to-Molecule Transformation on Video: The Bottom-Up Synthesis of Fullerene C60 from Truxene Derivative C60H30

“…Continuous video imaging allows for the structural analysis and monitoring of formed intermediates in real-time. Unlike in the case of frequently studied fullerenes ,− ,− or PAHs − ,− entrapped in carbon nanotubes, our molecule is found as an isolated entity on a graphene monolayer. This circumstance prevents the oligomerization process with other fullerenes or molecules and allows us to focus solely on the intramolecular processes in granular detail.…”

“…Hereby, substantial progress in the field of transmission electron microscopy (TEM) was made within the past decade. In the literature often described as single-molecule atomic-resolution real-time electron microscopy (“SMART-EM”) or “chemTEM”, , the direct imaging technique revealed to be especially powerful in the initiation and capture of nonrepetitive events. , For example, the formation of buckyballs from bilayered graphene, which reflects the top-down fullerene formation during the arc-discharge synthesis, was demonstrated in 2010 by Chuvilin et al Further recent highlights comprise the bimolecular reaction of fullerenes, , the reactivity of endohedral fullerenes and their entrapped molecules, the transformations of polycyclic aromatic hydrocarbons to oligomers, − the analysis of reactive metal clusters, − the bonding character of dimeric metal atoms, and even the emerging nucleation of a NaCl nanocrystal . Yet, a discrete multistep synthesis (molecule-to-molecule transformation), which leads to the predicted product and does not terminate in the formation of polymers, was never captured …”

Exclusive Substitutional Nitrogen Doping on Graphene Decoupled from an Insulating Substrate

“…In this specific case, this C 1s spectrum can be fitted almost exclusively by a single peak at 284.4 eV with a full width at half-maximum (fwhm) of 0.8 eV, which is in very good agreement with the values corresponding to graphene in synchrotron and lab-based photoemission experiments. ,, Furthermore, a shift of the C 1s can be expected because of the N incorporation on the lattice and the interaction with the specific metallic substrate, but the largest contribution to this core response arises from the sp 2 -hybridized C atoms. Regarding the N incorporation into the lattice of N-graphene grown on the Cu(111) substrate, Figure b,d shows the core level N 1s spectra where the components below 399 eV recorded straight after the molecular deposition correspond to the nitrilic and pyridinic bonding environments in agreement with the structure of the molecule . On the other hand, after annealing, the N-graphene spectrum is notoriously different.…”

Nitrogen‐Doped Porous Graphene Coated with Fe3O4 Nanoparticles for Advanced Supercapacitor Electrode Material with Improved Electrochemical Performance

“…All the N 1s spectra can be divided into pyridinic N (398.3 eV), pyrrolic N (399.9 eV), and graphitic N (401.5 eV), among which pyridinic N and pyrrolic N could contribute to the enhancement of specific capacitance through extra redox reactions, while graphitic N could mainly promote the conductivity of the materials and facilitate the rapid charging and discharging process. [ 26,28 ] Fe 2p spectra are also fitted and shown in Figure 5d. Two main peaks accompanied by a small satellite peak can be found in all the NPGF composites, which are ascribed to Fe 2p3/2 and Fe 2p1/2 respectively and can both be further deconvoluted into two peaks of Fe 2+ and Fe 3+ .…”

“…[ 22–25 ] What is more, as nitrogen atoms can not only provide extra electrons to the graphene layer and avoid graphene from excessive stacking, but also provide more defect sites for the synthesis of Fe 3 O 4 nanoparticles, nitrogen atoms are always doped into graphene layers to form nitrogen‐doped graphene. [ 26–31 ] To the best of our knowledge, although extensive research has been carried out on G/Fe 3 O 4 , researches on incorporating pore structures and nitrogen atoms simultaneously into the graphene layers of G/Fe 3 O 4 to improve its electrochemical performance are still scarce. Therefore, it will be extremely meaningful if low cost and simple synthesis of nitrogen‐doped porous graphene/Fe 3 O 4 composites can be achieved.…”