Synthesis of (B-C-N) Nanomaterials by Arc Discharge Using Heterogeneous Anodes

Abstract

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.

Perspectives on Thermal Plasma Modelling

“…The presence of catalyst should be taken into account because it may significantly change the ablation rate, for example [27]. …”

CVD-Synthesis of N-CNT Using Propane and Ammonia

“…A new approach to changing the chemical and electrical properties of CNTs is the modification of the carbon structure by a heteroatom, nitrogen. Currently, to obtain nitrogen-doped carbon nanotubes (N-CNTs), methods and approaches based on the direct formation of material from a nitrogen-containing carbon precursor or on the thermal treatment of undoped CNTs in a nitrogen-containing atmosphere are being developed [ 9 , 10 , 11 , 12 , 13 , 14 ].…”

CFD Analysis of Heat Transfer Phenomena in Arc Plasma Reactor

“…Thermal plasmas are widely used for the synthesis of nanomaterials [1][2][3], arc welding, cutting of metallic materials by plasma torch [4], plasma spraying [5], high and medium voltage circuit breakers [6], arc furnaces in metallurgy, high pressure lamps or vitrification and waste treatment [7]. Consequently, they are the subject of numerous research studies aiming to gain a better understanding of them and to anticipate the physical process that they generate.…”

“…In this work, a CFD study of a DC arc thermal plasma reactor is performed using the COMSOL tool. The reactor (shown in Figure 1), described in detail elsewhere [2,3,10] was developed for the Synthesis of carbon nanotubes, Briefly, it consists of a cylindrical vessel of about 30 cm in diameter and about 0.5 m in height, with two opposed quartz windows placed in front of the plasma and allowing observation of the arc and carrying out a spectroscopic study. The electrodes (two pure graphite rods of 6 mm in diameter) are placed in a vertical configuration to ensure the symmetry of the arc column.…”