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

An hydrogenated nitrogen-rich graphitic carbon nitride, structurally related to the theoretical graphitic phase of C3N4, has been synthesized in a bulk well-crystallized form. This new material was prepared by thermal decomposition of thiosemicarbazide up to 600 °C at ambient pressure under nitrogen flow. Its composition was determined by elemental combustion analysis. Powder X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy and C13 MAS NMR characterizations were performed. This material can be schematically described with a two-dimensional framework and a composition close to C3N4.17H1.12. In this nitrogen-rich material, C3N3 voids are fully occupied by water molecules which are strongly trapped into the material. A loss of crystallinity associated with a modification of the thermal behavior is observed when the amount of trapped molecules decreases in the graphitic material, order being damaged both between and in the graphitic planes.

Graphitic hydrogenated nitrogen-rich carbon nitride was synthesized at ambient pressure and mild temperature. The nitrogen overstoichiometry is explained by the presence of triazine voids in the graphene planes. The presence of trapped water molecules into these voids tends to influence the crystallinity and the thermal behavior of the materials.Figure optionsDownload as PowerPoint slide