Facile synthesis of graphene quantum dots and C-doping porous BN nanoribbon heterojunctions for boosting CO2 photoreduction

Herein, the graphene quantum dots (GQDs) as a photosensitizer have been introduced on the surface of C-doping porous BN nanoribbons (C-BNNR) to form a series of 0D/1D GQDs/C-BNNR heterojunctions as metal-free catalysts with excellent photocatalytic activity. the C-BNNR with sensitization of GQDs is innovatively applied to the field of CO2 photocatalytic reduction. The results reveal that GQDs/C-BNNR heterojunctions exhibit excellent optical properties and photocatalytic activity. The CO production rate of GQDs/C-BNNR-3 (33.47 μmol g-1h-1) is 14.49, 4.60 and 2.95 times higher than GQDs (2.31 μmol g-1h-1), BNNR (7.27 μmol g-1h-1) and C-BNNR (11.34 μmol g-1h-1), respectively. This work demonstrates that the addition of GQDs can significantly improve the light utilization of C-BNNR without any effect on the structure. In addition, the strong interaction between the GQDs and C-BNNR leads to the formation of a built-in electric field. It allows photogenerated electrons in GQDs to be transferred into C-BNNR and complexed with holes. As a result, the photogenerated electrons in C-BNNR are induced to participate in the CO2 photocatalytic reduction process. Meanwhile, GQDs/C-BNNR possess certain CO2 photocatalytic reduction ability in the NIR region due to the upconversion ability of GQDs. This work pioneer the application of GQDs/C-BNNR heterojunctions in CO2 photocatalytic reduction and further provides new ideas for the design of novel metal-free catalysts.