Biomass derived carbon dots mediated exciton dissociation in rose flower-like carbon nitride for boosting photocatalytic performance

Sustainable valorization of forestry waste products as substrate materials to realize energy conversion and environmental purification via the photocatalysis technology holds great promise due to its low cost, abundance and sustainability. The metal-free photocatalyst graphitic carbon nitride (CN) is known for its low toxicity, high stability, favorable optical properties, and controllable structure. Whereas, the strong exciton effects by Coulomb interactions between excited electrons and holes severely impede the enhancement of photocatalytic performance. Herein, by introducing biomass carbon quantum dots (prepared from ginkgo leaves, BQ) in rose flower-like carbon nitride (FCN), it was demonstrated that the construction heterojunction between BQ and FCN can not only facilitate the dissociation of excitons and the transfer of charge, but also enhance light absorption. As a result, in comparison with CN, the optimized zero dimension-three dimensions (0D–3D) BQ-FCN displayed much better photocatalytic hydrogen (H2) production rate (3400 μmol h−1 g−1) as well as better degradation performance of Rhodamine B (RhB), which is much higher than those carbon decorated CN and 3D CN photocatalysts in previous reports. It is believed that this work provides a meaningful guidance in using forestry waste materials to adjust the dissociation of excitons, and makes a significant process in the development of metal-free and highly efficient photocatalyst.