Combustion synthesis of carbon nanostructures by liquid-fuel flames in a stagnation-point flow

Carbon nanotubes were synthesized by ethanol diffusion flames in a stagnation-point liquid-pool system. In the stagnation-point flow field, both of the oxygen concentration and exit velocity strongly influenced the flame characteristics. Oxygen concentration and exit velocity dominated the formation of soot layer, extinction and position of the flame. Carbon nanotubes were synthesized at 25% and 15% oxygen concentrations when deposition time was 30 s. The temperatures at the corresponding sampling positions of 25% and 15% O ₂ were 1350°C and 430°C, respectively. A wide temperature range suitable for the synthesis of CNTs was found. However, SEM images showed great differences in morphologies and yields of synthesized products.