Synthesis of nitrogen-rich carbon nitride networks from an energetic molecular azide precursor

Nitrogen-rich carbon nitrides are produced as amorphous, bulk solids from t he slow thermal decomposition of 2,4,6-triazido-1,3,5-triazine [(C3N3)(N-3) 3] This energetic molecular azide is thermally unstable and readily decompo ses at 185 degreesC in a high-pressure reactor to produce carbon nitride ma terials, e.g., C3N4 Under: applied nitrogen gas pressure, (C3N3)(N-3)(3) de composes to yield a solid with one of the highest reported nitrogen-to-carb on ratios corresponding to C3N5. This azide precursor also decomposes upon rapid heating to 200 degreesC to form graphite nanoparticles without any re tained nitrogen. Spectroscopic evidence (infrared, nuclear magnetic resonan ce, and ultraviolet-visible) demonstrates that the carbon-nitrogen solids h ave significant sp(2) carbon bonding in a conjugated doubly bonded network. Electronmicroscopy reveals that these powders have a glassy microstructure with large irregular pores and voids. C3N4 and C3N5 are thermally stable u p to 600 degreesC and sublime to produce carbon nitride thin films on SiO2 and Si substrates. A discussion on possible azide decomposition pathways an d carbon nitride structures is presented.