Triamterene-Grafted Graphitic Carbon Nitride with Electronic Potential Redistribution for Efficient Photocatalytic Hydrogen Evolution.

Abstract

In this study, a photocatalyst with a distorted skeleton and synthesized by grafting triamterene onto graphitic carbon nitride (g-C3 N4 ) frameworks was prepared. The pteridine ring of the triamterene-based nitrogen-enriched organic structure functions as a trapped electron site owing to its inductive effect. The benzene ring in triamterene plays an important role in the even dispersion of electrons by a conjugative effect. Redistribution of the intramolecular electronic potential is caused by a synergistic effect between the pteridine and benzene rings of triamterene and promotes separation and migration of the photoinduced charge carriers. After coupling with triamterene, the π electrons of g-C3 N4 are relocated; that is, the intrinsic electronic and band structures of g-C3 N4 are effectively modulated. The modified polymeric photocatalyst shows a high photocatalytic H2 evolution rate of 157.5 μmol h-1 , a value that is 4.3 times higher than the H2 evolution rate of pristine g-C3 N4 (36.8 μmol h-1 ), with an apparent quantum efficiency of 9.7 % at λ=450 nm. The incorporation of triamterene into the g-C3 N4 frameworks significantly expands its π-delocalized system by redistribution of the electronic potential, expands the visible-light absorption range, and effectively promotes the separation and migration of photoinduced charge carriers. This strategy may provide a reference for promoting charge separation of g-C3 N4 through redistribution of the electronic potential and for synthesizing novel carbon nitride based semiconductors for efficient solar energy conversion into hydrogen.