Synthesis of (B-C-N) Nanomaterials by Arc Discharge Using Heterogeneous Anodes
Résumé
In spite of the current prevalence of the CVD-based processes, the electric arc remains an interesting process for the synthesis of carbon nanoforms, thanks to its versatility, robustness and easiness. It also allows performing in-situ substitution of carbon atoms by hetero-elements in the graphene lattice. Our work aims to establish a correlation between the plasma properties, type and chemical composition (and the substitution rate) of the obtained single-wall carbon nanotubes. The plasma was characterized by optical emission spectroscopy and the products were analyzed by high resolution transmission electron microscopy and core level Electron Energy-Loss Spectroscopy (EELS). Results show that a high boron content leads to a plasma temperature decrease and hinders the formation of nanotubes. This effect can be compensated by increasing the arc current and/or yttrium content. The optimal conditions for the synthesis of boron- and/or nitrogen-substituted nanotubes correspond to a high axial plasma temperature associated to a strong radial gradient. EELS analysis confirmed that the boron incorporates into the graphenic lattice.
Mots clés
Carbon nanotubes
Electric arcs
Electric discharges
Electron energy levels
Electron scattering
Electron temperature
Energy dissipation
High resolution transmission electron microscopy
Nanostructured materials
Nanotubes
Nitrogen plasma
Optical emission spectroscopy
Plasmas
Single-walled carbon nanotubes (SWCN)
Yarn
Arc discharge
Chemical compositions
Core-level electrons
Doped carbons
Optical spectroscopy
Optimal conditions
Plasma temperature
Substitution rates
Electron energy loss spectroscopy