Branched carbon nanotubes synthesized by pyrolysis of dimethyl sulfide over Fe/MgO catalyst and their luminescent property

The synthesis of carbon nanotubes (CNTs) by catalytic decomposition of dimethyl sulfide (C2H6S) over Fe/MgO catalyst has been investigated, and extensive characterization of the products has been carried out using scanning electron microscopy, high-resolution transmission electron microscopy (TEM), electron diffraction, Raman and photoluminescence (PL) spectroscopy. It is revealed that the experimental conditions strongly influence the microstructure and yield of the synthesized product. The appropriate C2H6S vapor concentration for the CNT growth is found to be around 2.67–4.96%. A large quantity of branched CNTs has been obtained in the C2H6S vapor concentration range of 2.67–3.86%, and their growth mechanism has been discussed according to the TEM observation. The branched CNTs are made of stacked conical graphite sheets with a cone angle of ∼30° to the tube axis. Due to the presence of the specific defects in the CNT Y-junction and the CNT surface, the branched CNTs exhibit an intensive violet PL emission at 406 nm and a strong blue PL emission at 486 nm.