Tuning the C/N Ratio of C‐Rich Graphitic Carbon Nitride (g‐C<sub>3</sub>N<sub>4</sub>) Materials by the Melamine/Carboxylic Acid Adduct Route
Arianit Gashi, Julien Parmentier, Philippe Fioux, Roman Maršálek
Abstract
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=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.