High-pressure pyrolysis study of C₃N₆H₆: a route to preparing bulk C₃N₄

Abstract

In order to prepare bulk C3N4, high-pressure pyrolysis of melamine (C3N6H6) at different temperatures was carried out. The products were characterized by C, N, H element analysis, Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy, and x-ray diffractometry. The results of the analysis reveal that graphitic phase C3N4 has been synthesized. It provides a novel route to synthesis of the theoretical superhard cubic C3N4 and other C3N4 phases from organic compounds by a high-pressure and high-temperature method.

Modulation of the crystallinity of hydrogenated nitrogen-rich graphitic carbon nitrides

“…In this material, it then seems obvious that nitrogen can adopt two main surroundings whether it is involved in triazine cycles or not. One should notice that the two main contributions evidenced on N 1s XPS spectrum are in agreement with those observed in case of melamine [21]. Calculating the ratio of the areas of the peaks at 399.9 and 398.3 eV, we obtain the atomic ratio of the two corresponding species, respectively.…”

“…The IR spectrum of rawsample ( Fig. 3a) is classical of that observed for graphitic carbon nitrides [15][16][17][20][21][22][27][28][30][31][32][33][34][35][36][37]. The absorptions between 1100 and 1700 cm -1 are typical for molecules that contain CN heterocycles (stretching vibrations of triazine ring).…”

“…Although nitrogen deficiency is common in carbon nitrides because of the stability of the easily-formed N 2 molecules, it was evidenced that mild experimental conditions involved in processes such as solvothermal reactions or thermal decomposition are favorable to retain nitrogen in the material, leading then to nitrogen-rich materials [9,[15][16][17][18]. The presence of hydrogen in raw-sample is not surprising as it is usually evidenced in carbon nitrides [9,[15][16][19][20][21][22][23]. Finally, the presence of oxygen, although in low content, should be noticed as well as the absence of sulfur in raw-sample.…”

Linear and nonlinear optical properties for AA and AB stacking of carbon nitride polymorph (C3N4)

“…The g-C 3 N 4 preparation has been described. [6][7][8][9][10][11][12][13][14][15][16][17][18][19] A hypothetical material, C 3 N 4 may have rather smaller bulk modulus than that of diamond as proposed by rst-principles calculations. 20,21 These outcomes have inspired theoretical calculations [22][23][24][25][26] and experimental efforts to synthesize and distinguish this compound.…”

Tackling the stacking disorder of melon—structure elucidation in a semicrystalline material

“…18,41 For nearly all cases hydrogen contents well above 1.6 wt-% were observed, which indicates the presence of oligo-or polymeric melon-type materials rather than of binary carbon nitride. 4,29,30,35,[42][43][44] The acquisition of accurate data beyond stoichiometry and composition remains largely elusive due to an inherent poor crystallinity and a high degree of disorder. X-ray powder patterns usually indicate a pronounced stacking disorder of neighboring layers with an interlayer distance amounting to about 3.2 Å .…”