Spectroscopy of π bonding in hard graphitic carbon nitride films: Superstructure of basal planes and hardening mechanisms

X-ray-absorption near-edge spectroscopy (XANES or NEXAFS) has been used to obtain information on the orientation, corrugation, and cross-linking of graphitic carbon nitride planes, structural parameters that determine the mechanical properties of the material. The contribution of p electrons from carbon and nitrogen atoms to {π} bonding in graphitic carbon nitride has been studied with elemental and angular sensitivity by XANES. The density of π* states from nitrogen is composition dependent and presents angular anisotropy, while the density of π* states from carbon is isotropic and independent of composition. Both observations are consistent with a model of the superstructure of basal planes.