Easy method to prepare N-doped carbon nanotubes by ball milling

N-doped carbon materials are promising metal-free catalysts for a number of applications. In this work, a cost effective and easy method to prepare N-doped carbon nanotubes by ball milling was developed, which avoids the use of solvents and production of wastes. Melamine and urea were used as nitrogen precursors. The textural and chemical properties of the N-doped materials were characterized by N2 adsorption at −196°C, temperature programmed desorption, elemental analysis, X-ray photoelectron spectroscopy and thermogravimetric analysis. The highest efficiency of N-doping was obtained with melamine. This method leads to the incorporation of large amounts of N-groups, namely quaternary nitrogen, pyridinic, and pyrrolic groups.