| 초록 |
Mesoporous carbon nitrides (MCN) with perfect stoichiometry C3N4 are fascinating materials because the doping of nitrogen in the carbon framework can significantly influence the electronic, electrical, mechanical, conducting and optical properties and are prominent candidates to complement carbon materials in a variety of energy, environmental, and biomedical applications. The definition of CN materials has been changed significantly from the ideal C3N4 stoichiometry and now the same has been extended to include compounds such as C3N, C3N2, C10N3, C5N, C3N5, C3N6, C3N7 etc., having lower or higher nitrogen content than the ideal C3N4 structure. The higher and lower nitrogen content with respect to the ideal C3N4 is attributed to the presence of structural defects which are affected by the reaction conditions, degree of condensation and relative reactivity of molecular CN precursors. In this study, highly ordered MCN materials with high nitrogen contents were successfully prepared through the polymerization of different aromatic and/or aliphatic carbon and high nitrogen containing molecular precursors via hard templating approaches. The most important findings here are arrived at: (i) new MCN materials had the large surface areas higher than 300 m2g-1 and tunable pore diameters from 3 nm and 8 nm with well-ordered 2- and 3-dimensional mesoporous structure; (ii) the MCN materials had a very high nitrogen content with a C/N ratio of less than 0.5, which is lower than theoretical C/N ratio of 0.75 for typical graphitic carbon nitrides; and (iii) the nitrogen-rich MCN materials showed the excellent CO2 adsorption capacity of more than 8.0 mmolg-1 at the temperature of 0 °C and pressure of 30 bar. The chemical bonding nature and electronic band structures of these novel MCN materials were also investigated by soft X-ray spectroscopy (NEXFAS data). The detailed results of CO2 conversion using novel MCN materials will be presented during the conference. |
