Large-scale synthesis of single-walled carbon nanohorns by submerged arc

We report on the synthesis of single-walled carbon nanohorns (SWNHs) by arc discharge between two graphite electrodes submerged in liquid nitrogen. The product in its powder form was found to consist of spherical aggregates with sizes in the range of 50–100 nm. The nanohorns are characterized by transmission electron microscopy (TEM), Raman and electron energy loss spectroscopies and surface area measurements. TEM observations revealed that the internal structure of the aggregates could be described as a mixture of 'dahlia-like' and 'bud-like'. A structural transition above 300 °C was inferred from the Raman data. Here we show that a simple technique that does not require relatively expensive laser and vacuum equipment provides an economical alternative for the synthesis of SWNHs.