Insight into the influence of donor-acceptor system on graphitic carbon nitride nanosheets for transport of photoinduced charge carriers and photocatalytic H2 generation

The rapid recombination of photogenerated charges is one of the main restriction for promoting the photocatalytic H-2 generation of graphitic carbon nitride (CN) material. Herein, donor-acceptor (D-A) system was introduced into CN nanosheets by oxygen and/or phenyl doping (DA-CN) strategy to facilitate the transport of photoinduced charge carriers and H-2 generation. Experimental and theoretical results revealed that the nanosheet structure of DA-CN shortened the photoexcited charges transport length to the surface, and the D-A system embedded in DA-CN provided the dipole-induced internal electric field for charges transport. As a consequence, compared with pristine CN, DA-CN samples performed the improved transport of photogenerated charges and photocatalytic H-2 evolution. Notably, DA-CN-OP (oxygen and phenyl co-doping) with the strongest dipole-induced internal electric field originated from D-A system displayed the highest photocatalytic H-2 evolution rate at 7.394 mmol g(-1)h(-1), which was 7.67 times as that of pristine CN (0.964 mmol g(-1)h(-1)). This work not only provides a simple strategy to construct highly efficient CN nanosheet photocatalyst with D-A system, but also promote the deep insight into the effect of molecular dipole originated from D-A system on the transport of photoinduced charge carriers and photocatalytic activity for CN material. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

The rapid recombination of photogenerated charges in graphitic carbon nitride (CN) material limits the photocatalytic H-2 generation efficiency. Introducing a donor-acceptor (D-A) system can improve the transport of photoinduced charge carriers, with oxygen and/or phenyl doping in CN nanosheets showing promising results in photocatalytic H-2 evolution.