Nitrogen-carbon graphite-like semiconductor synthesized from uric acid

Abstract

A new carbon-nitrogen organic semiconductor has been synthesized by pyrolysis of uric acid. This layered carbon-nitrogen material contains imidazole-, pyridine (naphthyridine)-and graphitic-like nitrogen, as evinced by infrared and X-ray photoelectron spectroscopies. Quantum chemistry calculations support that it would consist of a 2D polymeric material held together by hydrogen bonds. Layers are stacked with an interplanar distance between 3.30 and 3.36 Å, as in graphite and coke. Terahertz spectroscopy shows a behavior similar to that of amorphous carbons, such as coke, with non-interacting layers. This material features substantial differences from polymeric carbon nitride, with some characteristics closer to those of nitrogen-doped graphene, in spite of its higher nitrogen content. The direct optical band gap, dependent on the polycondensation temperature, ranges from 2.10 to 2.32 eV. Although in general the degree of crystallinity is low, in the material synthesized at 600 °C some spots with a certain degree of crystallinity can be found.

Comparison of the activities of C2N and BCNO towards Congo red degradation

“…The bands at 1580 and 1240 cm -1 could be ascribed to vibrations of rings containing 6-5 nitrogen atoms: the band at 1580 cm -1 may be related to ring stretching vibrations from both pyridine-like and imidazole (or pyrrole)-like rings, while C-N stretching of imidazolelike rings would generate the band at 1240 cm -1 . From this point of view, the infrared spectrum would be similar to that previously obtained for nitrogen-doped graphene [17,[23][24][25].…”

“…3000 cm -1 was connected to OH stretching vibrations, all interacting by hydrogen bond. A detailed assignations of bands can be found in a previous report by Dante et al [17].…”

“…In a previous experimental work, we reported that a material with a N to C atomic ratio ~0.6, featuring a polymer structure and electronic properties that differed from those of g-C 3 N 4 , could be obtained from the pyrolysis of a mixture of uric acid and melamine [17]. The characterization results suggested that such C 2 N would be a polymeric semiconductor, featuring a very organized 2-D supramolecular structure, with a diffused and strong network of hydrogen bonds.…”

“…This layered carbon-nitrogen material contained imidazole-, pyridine (naphthyridine)-and graphiticlike nitrogen. The newly synthesized material presented herein was obtained in a similar way to that reported in [17], but in this case no melamine was added to the reaction blend, in such a way that the resulting material was obtained only from the pyrolysis of pure uric acid. Although it was expected to be similar to the previously reported one, it was found to exhibit new and dissimilar properties.…”

Facile Synthesis of Lacunary Keggin-Type Phosphotungstates-Decorated g-C3N4 Nanosheets for Enhancing Photocatalytic H2 Generation

“…Meanwhile, the other peaks on the diffraction pattern of the Na-PW 9 were also matched with that of the reported PW 9 , confirming the obtained lacunary Keggin-type phosphotungstates of PW 9 . In the case of g-C 3 N 4 NSs, the two feature diffraction peaks, belonging to the periodic structure of intra-planar tri-s-triazine and the interlayer stacking of conjugated aromatic structures of g-C 3 N 4 NSs were found at 13.1° and 27.4°, respectively [ 25 , 26 , 27 , 28 ]. This is in agreement with the graphite structure of carbon nitride.…”