Tuning the C/N Ratio of C-Rich Graphitic Carbon Nitride (g-C3 N4 ) Materials by the Melamine/Carboxylic Acid Adduct Route

Arianit Gashi; Julien Parmentier; Philippe Fioux; Roman Marsalek

doi:10.1002/chem.202103605

Tuning the C/N Ratio of C-Rich Graphitic Carbon Nitride (g-C₃ N₄ ) Materials by the Melamine/Carboxylic Acid Adduct Route

Chemistry. 2022 Mar 7;28(14):e202103605. doi: 10.1002/chem.202103605. Epub 2022 Feb 19.

Authors

Arianit Gashi^{1

2}, Julien Parmentier², Philippe Fioux², Roman Marsalek¹

Affiliations

¹ Department of Chemistry, University of Ostrava, 30. Dubna 22, Ostrava, 701 03, Czech Republic.
² Institut de Science des Matériaux de Mulhouse (IS2 M), Université de Strasbourg, Université de Haute-Alsace, 15 rue Jean Starcky, BP 2488, 68057, Mulhouse Cedex, France.

PMID: 35107841
DOI: 10.1002/chem.202103605

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-C₃ N₄ 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-C₃ N₄ structure. This trend is followed by a significant increase in the interlayer spacing and a lower proportion of N=C-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.

Keywords: adducts; carbon-rich g-C3N4; carbonitrides; doping; supramolecular chemistry.