Synthesis of Carbon Nanotubes Using a Butane−Air Bunsen Burner and the Resulting Field Emission Characteristics

Abstract

Multiwalled carbon nanotubes (MWCNTs) with uniform diameters (10−20 nm) and high densities per unit area were synthesized in a 5−10 s combustion process using a mixture of butane and air at 880 °C. The growth mechanism of MWCNTs was studied via time-sequence experiments to reveal that the catalyst nanoparticles were formed on a 3 nm thick Ni-coated wafer after 3 s in the flame. Short and uniform MWCNTs were synthesized using a 5 s process, whereas MWCNTs with a maximum density and length were obtained using a 10 s process. It is believed that both the synthesis temperature and the combustion products, such as CO, H2O, C n H m (n = 1 or 2), and polycyclic aromatic hydrocarbons, play an important role in the growth of the MWCNTs. Furthermore, the field emission properties of the combustion-generated carbon nanotube (CNT) films were studied, and an emission current density of 0.18 mA/cm2 at 7 V/μm was obtained. These results suggested that this fabrication method provided rapid and direct growth of field-emission CNTs on a desired substrate.

Locally Controlled Growth of Individual Lambda‐Shaped Carbon Nanofibers

“…Pan and Bao demonstrated growth of CNFs in an open ethanol flame in 2002 . Inspired by this and other studies, we grew CNFs from NiCl 2 ·6H 2 O on silicon substrate completely covered with a thin 60 nm copper layer in an open ethanol flame and studied the adhesion properties of the resulting CNF arrays . Considering the simplicity and cost‐effectiveness of this process, it is surprising that it works without the usual reduction step, where the catalyst gets reduced by hydrogen or ammonia gas .…”

“…Other approaches like welding of selected CNTs by electron beams are most likely beyond any commercial application . Alternative growth processes utilizing an open flame from a paraffin wax candle, a butane‐based Bunsen burner, or an ethanol burner are less demanding regarding machinery, process gases, and energy input. However, compared to conventional CVD or plasma‐enhanced CVD processes, which are widely described in textbooks, they are only sparsely examined up to now.…”

Dry adhesives from carbon nanofibers grown in an open ethanol flame

“…They need only an open flame, which serves as the carbon source and provides the necessary temperature. Li and Hsieh demonstrated the growth of multiwalled carbon nanotubes (MW-CNTs) from the flame of a paraffin wax candle [ 7 ] and a Bunsen burner [ 8 ]. Pan and co-workers grew CNTs and CNFs with an ethanol flame [ 5 ] and demonstrated possible alignment during growth with an external electric [ 6 ] or magnetic field [ 9 ].…”

Combustion Chemistry of the Butane Isomers in Premixed Low-Pressure Flames

“…Butane partial oxidation is also an important source of maleic anhydride as precursor to, e.g. polyether resins [24], and butane flames may be used in the combustion synthesis of multi-walled carbon nanotubes [25].…”