Structure and electronic structure of S-doped graphitic C₃N₄ investigated by density functional theory

The structures of the heptazine-based graphitic C₃N₄ and the S-doped graphitic C₃N₄ are investigated by using the density functional theory with a semi-empirical dispersion correction for the weak long-range interaction between layers. The corrugated structure is found to be energetically favorable for both the pure and the S-doped graphitic C₃N₄. The S doptant is prone to substitute the N atom bonded with only two nearest C atoms. The band structure calculation reveals that this kind of S doping causes a favorable red shift of the light absorption threshold and can improve the electroconductibility and the photocatalytic activity of the graphitic C₃N₄.