Identification of new pillared-layered carbon nitride materials at high pressure

Abstract

The compression of the layered carbon nitride C6N 9H3 ·HCl was studied experimentally and with density functional theory (DFT) methods. This material has a polytriazine imide structure with Cl- ions contained within C12N12 voids in the layers. The data indicate the onset of layer buckling accompanied by movement of the Cl- ions out of the planes beginning above 10-20 GPa followed by an abrupt change in the diffraction pattern and c axis spacing associated with formation of a new interlayer bonded phase. The transition pressure is calculated to be 47 GPa for the ideal structures. The new material has mixed sp2-sp3 hybridization among the C and N atoms and it provides the first example of a pillared-layered carbon nitride material that combines the functional properties of the graphitic-like form with improved mechanical strength. Similar behavior is predicted to occur for Cl-free structures at lower pressures.