Construction of binary donor–acceptor conjugated copolymer in g-C3N4 for enhanced visible light-induced hydrogen evolution.

By skillfully introducing a conjugate electron donating ring into the g-C 3 N 4 framework, the as-prepared 3 wt% PPD/CN sample not only narrows the bandgap of g-C 3 N 4 , but also absorbs more solar light up to 600 nm. As a result, the optimal sample exhibited hydrogen escape under orange light (600 nm) and bare g-C 3 N 4 had almost no such performance. [Display omitted] • Benzene ring doping in the specific site of the network of g-C 3 N 4 was obtained. • It still has photoactivity that g-C 3 N 4 barely has under the orange light. • The 3 wt% PPD/CN can effectively cover more sufficient photo flux (λ = 600 nm). • The benzene ring incorporation of g-C 3 N 4 enhanced photogenerated carrier separating. Grafting π-conjugated donor units into graphitic carbon nitride (g-C 3 N 4) represents a promising alterative to improve its light absorption range and charge transfer kinetics. To this end, we here report an efficient intramolecular g-C 3 N 4 -based conjugated copolymers via the one-spot thermal copolymerization for not only reduces the bandgap to 2.56 eV and thus expand the visible-light harvesting capability, but also accelerates the separation ability of photogenerated excitons. Consequently, the copolymer of 3 wt% p-phenylenediamine with melamine exhibits extraordinary hydrogen (H 2) evolution rate of 1040 μmol g−1 h−1 under visible light. Interestingly, it still shows hydrogen production (5.29 μmol g−1 h−1) at λ = 600 nm (orange light). Systematic characterizations have proved that the optimal sample has high photocatalytic activity, due to rapid charge transfer kinetics and exciton separation. Our work sheds light on a molecular design to regulate charge-transfer dynamics among of polymeric semiconductors towards efficient solar-to-H 2 production. [ABSTRACT FROM AUTHOR]