Boosted photocatalytic activity by depositing carbon quantum dots as electron mediator and photothermal-assisted site in dual heat source-based sponge

Herein, carbon quantum dots (CQD) and CoO nanoparticles were loaded as double heat sources in the hollow porous sponge g-C 3 N 4 with photothermal effect, and the CQDs/CoO/PMSCN Z-scheme heterojunction photothermal assisted photocatalytic system was constructed. Meanwhile, a series of characterization and DFT calculations were used to reveal the electron transfer mode inside the heterojunction. The photocatalytic degradation activity was enhanced by coupling the photothermal effect of multiple heat sources with the electron transfer in the heterojunction, and CQDs-2/CoO/PMSCN exhibited a TC degradation rate of 94.7 % after 90 min of light reaction. Notably, after five cycles of experimentation, the degradation rate decreased by only 4 %, demonstrating the material’s good stability and reusability. Additionally, the unique three-dimensional hollow porous structure of PMSCN allows incident light to penetrate and undergoes multiple reflections/refractions. This not only improves the light response range, but also provides certain thermal insulation, reducing heat loss. Finally, the ECOSAR assessment and bean sprout experiments indicated that TC degradation proceeded towards lower toxicity and non-toxicity. These findings highlight the effectiveness of CQDs/CoO/PMSCN for the treatment of antibiotic contamination, maximize energy utilization, and offer new insights for the practical application of CQDs.