Synthesis of Carbon Nanotubes from Ethanol Using RF-CCVD and Fe–Mo Catalyst

Abstract

Multiwalled carbon nanotubes (MWCNTs) were synthesized by RF (radio frequency) heating at 850 • C using an MgO-supported bimetallic Fe-Mo catalyst. Ethanol was used as the carbon source. The MWCNTs were tested using Raman spectroscopy, highresolution transmission electron microscopy (HRTEM), and thermogravimetric analysis (TGA). HRTEM studies show nanotubes with an average diameter of 16.0 ± 3.5 nm. In Raman spectroscopy, the ratios of intensities of the G and D band and the 2D and G bands were 0.90 and 0.47, respectively. These ratios are generally indicative of high crystallinity and purity of the MWCNTs. The purity of MWCNTs was calculated from TGA analysis.

Induction Heating: An Enabling Technology for the Heat Management in Catalytic Processes

“…This feature matches well with a high-temperature and energy-consuming process such as the catalytic chemical vapor deposition applied to C-nanomaterials production. In this regard, rf heating has been successfully applied to the high-quality production of single-walled (SW), double-walled (DW), and multiwalled carbon nanotubes (MWCNTs) − by lowering the energy consumption and shortening the overall reaction times in comparison to classical oven-heated reactors. Preliminary data have shown the use of various mono- or binary-transition-metal mixtures as such (Ni, Pd, Co, Co/Ni, Pd/Rh, Pt/Rh, Fe/Mo, , Fe/Co , ) or as NPs on metal oxides (TiO 2 , Al 2 O 3 , MoO 2 , , CaCO 3 ) to be housed into the reactor on molybdenum or copper foils or graphite vessels as susceptors for the rf heating.…”

“…In this regard, rf heating has been successfully applied to the high-quality production of single-walled (SW), double-walled (DW), and multiwalled carbon nanotubes (MWCNTs) − by lowering the energy consumption and shortening the overall reaction times in comparison to classical oven-heated reactors. Preliminary data have shown the use of various mono- or binary-transition-metal mixtures as such (Ni, Pd, Co, Co/Ni, Pd/Rh, Pt/Rh, Fe/Mo, , Fe/Co , ) or as NPs on metal oxides (TiO 2 , Al 2 O 3 , MoO 2 , , CaCO 3 ) to be housed into the reactor on molybdenum or copper foils or graphite vessels as susceptors for the rf heating. Heat is originated by the electromagnetically induced eddy currents flowing through the electrical resistance of the susceptor (Mo, Cu, or graphite foils, Fe or Ti rods), and it is transferred by conduction/radiation to the metal active sites.…”

“…Heat is originated by the electromagnetically induced eddy currents flowing through the electrical resistance of the susceptor (Mo, Cu, or graphite foils, Fe or Ti rods), and it is transferred by conduction/radiation to the metal active sites. The external reactor walls are kept cold (“cold reactor”), and the thermal decomposition of gaseous reagents is significantly reduced, whatever the nature of the carbon source used. , All of these contributions outline the deeply beneficial effects of rf-heated catalysis in comparison to the traditional conduction-based (outer reactor furnaces) protocols. rf-cCVD significantly reduces the energy consumption and shortens the reaction time.…”

“…The external reactor walls are kept cold ("cold reactor"), and the thermal decomposition of gaseous reagents is significantly reduced, whatever the nature of the carbon source used. 66,68 All of these contributions outline the deeply beneficial effects of rf-heated catalysis in comparison to the traditional conduction-based (outer reactor furnaces) protocols. rf-cCVD significantly reduces the energy consumption and shortens the reaction time.…”