Tailoring the structure and nitrogen content of nitrogen-doped carbon nanotubes by water-assisted growth

Vertically aligned nitrogen-doped carbon nanotubes (NCNTs) were synthesized by the pyrolysis of acetonitrile in the presence of ferrocene catalyst (2 wt.%) with water assistance. Herein, we demonstrated that water could be a special tool to shape the structure of the NCNTs and it can be injected as much as 33.3 wt.% to grow NCNTs. More significantly, the nitrogen content of NCNTs and their tubular microstructures including tube diameter and wall thickness can be finely tailored by water introduction, which may further modulate their film electrical conductivity and electrocatalytic activities for oxygen reduction reactions.