Construction of 2D polyoxoniobate/RGO heterojunction photocatalysts for the enhanced photodegradation of tetracycline

A series of polyoxoniobate based nanocomposites Nb-RGO-X were successfully preparedviaone-step solvothermal method.Among them, Nb-RGO-0.5 exhibits the most excellent photocatalytic activity towards photodegradation of tetracycline with the rate of 74.69% at 9 min. This work represents the first evidence of PONb-based heterojunction photocatalyst for photodegradation of antibiotics. [Display omitted] •Polyoxoniobate/RGO heterojunction photocatalysts was constructed for the first time.•The nanocomposite exhibited a photocatalytic degradation of tetracycline with rate of 74.69% in 9 min.•The photocatalytic mechanism has been studied and discussed extensively. Developing low-cost and efficient photocatalysts for photodegradation of antibiotics has been viewed as an effective method for wastewater treatment. Herein, the water soluble Lindqvist type K7HNb6O19 has been selected as precursor to combine with RGO, obtaining series heterogeneous photocatalysts Nb-RGO-X (X = 0.125, 0.25, 0.375, 0.5, 0.625, 0.75, X is the millimolar amount of K7HNb6O19 added to the 12 mL dispersion liquid containing 4 mg GO during synthesis.) under solvothermal condition. The Nb-RGO-0.5 displays an excellent stability, recyclability, and catalytic activity for photodegradation of tetracycline with the rate of 74.69% at 9 min. The construction of heterojunction in photocatalyst can effectively enhance the separation of photogenerated electrons and holes, charge transfer efficiency and broaden the absorption of light, leading to higher photocatalytic efficiency. To our best knowledge, Nb-RGO-X presents the first example of polyoxoniobate-based nanocomposites for photodegradation of antibiotics. Furthermore, the photocatalytic mechanism was proposed based on XRD, FT-IR, SEM, TEM, Raman, UV–vis DRS, XPS, PL, ESR, electrochemical measurements and reactive species trapping experiment. This work may contribute to the potential application of POM-based photocatalysts in wastewater treatment.