Visible light-induced photocatalytic degradation of tetracycline based on Cu/CDs/BiVO₄ ternary core-shell composite: DFT calculations and mechanism

The novel Cu/Carbon dots/BiVO₄ ternary core-shell material was prepared by hydrothermal method and applied for the photocatalytic degradation of tetracycline. The CCB-2 composite exhibited the best photocatalytic activity (96.8 %). The ·O₂^- and h⁺ were confirmed the main substances by electron spin response detection. The cycling experiments showed that CCB-2 has outstanding stability and recyclability. Based on calculations, energy band theory and intermediates analysis, the charge transfer pathways in the photocatalytic process were revealed. The photocatalytic mechanism and degradation pathways were elaborated. It was found that the built-in electronic fields were established in the ternary composite and the electrons can easily transfer from inner core Cu to interlayer carbon dots and then to outlayer BiVO₄. The Cu/Carbon dots/BiVO₄ composite obtained the effective separation of photocatalytic carriers after the irradiation and then showed the excellent performance. This study provided a promising strategy to enhance the application of bismuth-based materials in environmental purification.