Synthesis of nitrogen-doped carbon nanostructures by the reactions of small molecule carbon halides with sodium azide

Nitrogen-doped carbon nanostructures including particles, whiskers, square frameworks, lamellar layers, hollow spheres, and tubular structures have been successfully synthesized by designed direct chemical reactions of small molecule carbon halides (such as CCl4, C2Cl6) and nitridation reagent NaN3 in the absence of any templates and catalysts. The N/C ratios of the as-prepared CNx nanostructures (0.01 approximately 0.33) are strongly and systematically related to the reaction temperatures and the choice of carbon sources, as well as the presence or absence of the solvent. The Raman spectra indicate that the approaching graphitization process has occurred as the reaction temperature increases. The possible reaction mechanisms for the formation of the hollow structures are tentatively discussed according to the experimental results. This strategy provides an alternative route to synthesize nitrogen-doped carbon nanostructures and is expected to open up a new route for the synthesis of carbon nitrides.