“Recovering Pure N-CNTs”:

• Dissolving catalyst in concentrated nitric acid medium.

Precursor Selection Method:

• Selects from nontoxic nitrogenous materials.
• Examples: melamine, dicyandiamide, thiourea, urea, guanidine hydrochloride.

Catalyst Method Overview:

• Utilizes metal nanoparticles.
• Catalyzes metal alloys, oxides, hydroxides.

Nanoparticle Selection Method:

• Selects nanoparticles from metals (Fe, Ni, Co, Mo).
• Combines metal alloys (Fe-Sn, Fe-Mo, Fe-Ni, ZrMnNi0.5Fe0.5, ZrMnFeNiCo).
• Combines metal oxides (Fe304, NiO).
• Combines metal hydroxides (Co(OH)2 or Ni(OH)2).

Synthesizing N-CNTs:

• Uniform diameter with 20 nm outer diameter.
• Variance within 10%.

Synthesized N-CNTs: Bamboo-like Structure:

• d spacing of 0.34 nm.
• Highly nitrogenized with 12 ± 3% N.
• Currently amended method.

Heating g-C3N4 to Decompose to Ammonia and Hydrocarbons:

• Heats g-C3N4 to 800-1000 °C.
• Ammonia and hydrocarbons react to form N-CNTs on catalyst surface.