Realizing efficient exciton dissociation in an all-organic heterojunction photocatalyst for highly improved photocatalytic H2 evolution

Although graphitic carbon nitride is a promising photocatalyst in the field of energy con-version and environmental purification, the intrinsic properties like excitonic effects and sluggish charge transfer restrict further photocatalytic applications. To circumvent these limitations, the novel all-organic heterojunction photocatalysts were constructed by anchoring organic carbon dots (O-dots) on porous graphitic carbon nitride nanosheets (O-dots/CNS). Results demonstrated that excitons can be effectively dissociated into electrons and holes at the interface of O-dots/CNS heterojunction, followed by holes injected to O-dots and electrons accumulated in CNS to realize efficient charge separation. Conse-quently, the O-dots/CNS with the optimized hydrogen (H2) evolution performance could be reached 1564.5 mmol h-1g-1 under the visible light irradiation. This work not only presents new ideas for rational design photocatalytic reaction system from exciton and charge carrier, but also broaden the applications of this new kind of organic dots in the field of energy conversion.(c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

Novel all-organic heterojunction photocatalysts were constructed by anchoring organic carbon dots on porous graphitic carbon nitride nanosheets, which effectively dissociated excitons into electrons and holes and achieved efficient charge separation. The optimized O-dots/CNS catalyst exhibited a hydrogen evolution performance of 1564.5 mmol h-1g-1 under visible light irradiation. This study not only provides new ideas for the rational design of photocatalytic systems based on excitons and charge carriers, but also expands the applications of organic dots in the field of energy conversion.