Dual-defects modified ultrathin 2D/2D TiO2/g-C3N4 heterojunction for efficient removal of levofloxacin: Performance, degradation pathway, and mechanism

Novel dual-defect mediated ultrathin 2D/2D TiO 2 /g-C 3 N 4 Var Der Waals heterojunction exhibited excellent photocatalytic activities. • Defect-rich 2D/2D TiO 2 /g-C 3 N 4 VDW heterojunction was designed and fabricated; • The as-prepared heterojunction exhibited a superior photocatalytic activity for LVFX degradation; • Possible mechanisms and degradation pathways of LVFX degradation were proposed. Developing high-efficiency photocatalysts to eliminate fluoroquinolone antibiotics from the water matrixes remains a challenge. Therefore, a novel dual-defects modified 2D/2D TiO 2 /g-C 3 N 4 Van Der Waals heterojunction was constructed via surfactant-assisted and NaBH 4 thermal treatment, in which the TiO 2-x were anchored on the defect-rich g-C 3 N 4 sheets with an atomic-level intimate heterojunction interface. The as-prepared Dual-defects modified TiO 2 /g-C 3 N 4 exhibited the highest catalytic activity and 94.5% levofloxacin (LVFX) was decomposed within 15 min. The outstanding performance could be primarily ascribed to a special 2D structure, wide visible light response range, and high-efficiency separation and transfer of photogenerated carriers. Meanwhile, photocatalytic activity under different conditions was also studied, and the presence of CO 3 2- and pH values exhibit an obvious impact on catalytic activity. The possible LVFX degradation pathways were proposed, and the toxicity of the degradation produces was assessed via the quantitative structure-activity relationship (QSAR) method. Finally, a possible photocatalytic mechanism in dual defective TiO 2 /g-C 3 N 4 was proposed.