Steering charge kinetics boost the photocatalytic activity of graphitic carbon nitride: heteroatom-mediated spatial charge separation and transfer

Abstract

Charge kinetics plays a vital role in determining the quantum efficiency of solar-to-chemical conversion in photocatalysis. For most layered compounds, the photocatalytic performance is largely hindered by its sluggish charge transfer kinetics. Herein, we propose a novel strategy—heteroatom-mediated spatial charge separation and transfer—to accelerate photogenerated charge kinetics for boosting the photocatalytic performance of graphitic carbon nitride (CN). Both the experimental results and first-principle calculations show that out-of-plane charge transport and in-plane charge separation within CN nanosheets can be accelerated via F intercalation and B intralayer modification. The B implantation could realize in-plane charge-separation by spatial separation of HOMO and LUMO to promote efficient exciton dissociation, and the F heteroatom, as interlayer electron channel, accelerates the out-of-plane oriented charge transport. The visible-light photocatalytic activity of codoped CN nanosheets is greatly boosted via modulating the charge kinetics, which can be demonstrated by degrading methyl orange and colorless phenol as models. Moreover, the samples exhibit excellent photo-electrocatalysis OER activity, outperforming the metal CoSe2 catalyst. The enhanced catalytic activities are attributed to synergistically utilizing 2D ultrathin structural advantage and accelerating charge kinetics. This work proposes a novel strategy to tune charge carrier separations and migrations in functionalized 2D layered materials for environmental catalysis and advanced energy.HighlightsA novel heteroatom-mediated spatial charge separation and transfer strategy is proposed in B/F codoped CN nanosheets.Both the experimental results and first-principle calculations show that photogenerated charge kinetics can be accelerated within B/F codoped CN nanosheets.The B implantation could realize in-plane charge-separation by spatial separation of HOMO and LUMO to promote efficient exciton dissociation.The F heteroatom, as interlayer electron channel, accelerates the out-of-plane oriented charge transport.The optimized B/F codoped CN nanosheets have highly efficient catalytic activity for degrading organic pollutant and OER activity.