Tuning the C/N Ratio of C‐Rich Graphitic Carbon Nitride (g‐C₃N₄) Materials by the Melamine/Carboxylic Acid Adduct Route

Abstract

C-rich graphitic carbonitride materials (CN x ) with a large range of compositions have been prepared thanks to the self-assembly, in different ratios, of melamine (M) and a panel of polycarboxylic acids (A) such as oxalic, tartaric and citric acid. The thermal conversion of the formed adducts (MA y ), led to CN x phases, with x ranging from 0.66 to 1.4 (x = 1.33 for g-C 3 N 4 for comparison). The properties of these materials were examined by different techniques (XRD, Raman spectroscopy, TEM, TGA, XPS and DRIFT). It appears that the increase in the C content is associated with the disappearance of the long-range order of heptazine units and an increase in the sub-nanometer carbon-rich cluster size within the graphitic g-C 3 N 4 structure. This trend is followed by a significant increase in the interlayer spacing and a lower proportion of N=CÀ N bonds compared to C=C bonds. The thermal stability under an inert atmosphere of these phases and their UV-Visible absorbance properties were also investigated.

Ultrafast carrier transport in ultrafine porous 2D polymers for the highly selective photocatalytic reduction of CO2to CH4

“…1e), the two peaks at 399.6 and 401.1 eV are attributed to P]N and C-N]C, respectively. 32 The P 2p signals have two peaks at 135.2 eV and 133.7 eV due to the presence of P 2p 3/2 and P 2p 1/2 signals, respectively (Fig. 1f).…”

Water-Dispersible Carboxymethyl Dextran-Coated Melamine Nanoparticles for Biosensing Applications

“…Three bands from 1300 to 1600 cm −1 (methylene-derived C−H bending (1348, 1492 cm −1 ) and triazine-derived C�N stretching (1561 cm −1 )) in the spectrum of the MNPs were shifted to shorter wavenumbers after modification with CMD (C−H bending (1345, 1488 cm −1 ) and C�N stretching (1556 cm −1 )), indicating that hydrogen bonding caused by the carboxyl and hydroxyl groups of CMD weakened the interatomic bonding. 43 Subsequently, immobilization of SA shifted the band toward longer wavenumbers (C−H bending (1352, 1504 cm −1 ) and C�N stretching (1580 cm −1 )) from those of the original MNPs (Figure S3b). These shifts might arise from strong electrostatic interactions between the charged amino acid residues on the SA surface and the melamine resin.…”

“…The FT-IR spectral band assignments based on literature data are listed in Table S1. , All bands were derived from the melamine formaldehyde resin, indicating that the nanoparticle composition is almost exclusively melamine. Three bands from 1300 to 1600 cm –1 (methylene-derived C–H bending (1348, 1492 cm –1 ) and triazine-derived CN stretching (1561 cm –1 )) in the spectrum of the MNPs were shifted to shorter wavenumbers after modification with CMD (C–H bending (1345, 1488 cm –1 ) and CN stretching (1556 cm –1 )), indicating that hydrogen bonding caused by the carboxyl and hydroxyl groups of CMD weakened the interatomic bonding . Subsequently, immobilization of SA shifted the band toward longer wavenumbers (C – H bending (1352, 1504 cm –1 ) and CN stretching (1580 cm –1 )) from those of the original MNPs (Figure S3b).…”

Conducting Carbon Rich Graphitic Carbon Nitride Nanosheets with Attached Nano Sulfur Copolymer as High Capacity Cathode for Long‐Lifespan Lithium‐Sulfur Battery

“…Furthermore, strong bands at ~1411, 1485, 1567, and 1622 cm À 1 are observed in pristine GCN, which correspond to stretching vibration modes of heptazine derived units. [61][62][63] The bands corresponding to stretching vibration of partial condensation (CÀ NHÀ C) or full condensation (CÀ N(À C)À C) at ~1240 and 1330 cm À 1 are observed in pristine GCN. Due to decrement in nitrogen content in carbon-rich samples, the intensities of above mentioned peaks arising due to stretching vibration modes of heptazine derived units and full or partial condensation units decrease continuously with enhancement of carbon ratio in the synthesized material (C(20)GCN).…”