Hydrogen-free spray pyrolysis chemical vapor deposition method for the carbon nanotube growth: Parametric studies

► Spray pyrolysis CVD in the absence of hydrogen at low carrier gas flow rates. ► CNTs on semiconducting silicon wafer, carbon microfibers, and stainless steel plates. ► CNT average length and diameter decrease with temperature and injection speed. ► Catalyst concentration influences the bimodal diameter distribution of CNTs.