Enhanced electron delocalization on pyrimidine doped graphitic carbon nitride for boosting photocatalytic hydrogen evolution

The photocatalytic activity of graphitic carbon nitride (g-C₃N₄) depends to a large extent on its morphology and electronic band structure. In order to design a photocatalyst with suitable structural property and high efficiency of photo-generated carrier separation, herein, the pyrimidine doped g-C₃N₄ is prepared by a conventional one-pot copolymerization of urea and 2,4,6-Triaminopyrimidine (TAP). Such TAP organic molecule can not only regulate the electronic structure of conjugated system and distort heptazine units, but also affect the polymerization of precursor urea. As expected, the optimized photocatalyst shows a high photocatalytic hydrogen evolution activity of 453 μmol·h⁻¹ under visible light irradiation, which is 4.41 times over that of pure g-C₃N₄. Such enhanced photocatalytic performance is attributed to the introduction of pyrimidine ring which facilitates the electrons delocalization in the in-plane structure, enlarges the specific surface area, and broadens the visible light absorption range.