Highly efficient visible/near-infrared light photocatalytic degradation of antibiotic wastewater over 3D yolk-shell ZnFe2O4 supported 0D carbon dots with up-conversion property

The development of effective visible and near-infrared photocatalysts is highly promising in the current field of photocatalysis. Herein, carbon dots/ZnFe2O4 (CDs/ZFO) with coating zero dimensional (0D) CDs on the surface of three dimensional (3D) yolk-shell ZFO spheres was designed and synthesized via a self-templated solvothermal method. The as-prepared CDs/ZFO composites displayed outstanding visible and near-infrared photocatalytic degradation activity of tetracycline (TC), and the optimal 3% CDs/ZFO sample with loading 3% (mass) CDs displayed the highest photocatalytic TC degradation ability under visible light (79.5% within 120 min) and near-infrared light (41% within 120 min). The enhancement of photocatalytic activity for CDs/ZFO composite is mainly ascribed to the fact that 0D/3D yolk-shell CDs/ZFO structure not only effectively reflect the incident light to increase the utilization efficiency of solar light, but also utilize the up-conversion photoluminescence and electronic conductivity properties of CDs to broaden sunlight absorption range and promote separation and transfer of electron-hole pairs.