Fabrication of nitrogen doped graphene quantum dots-BiOI/MnNb2O6 p-n junction photocatalysts with enhanced visible light efficiency in photocatalytic degradation of antibiotics

- We have prepared the NGQDs-BiOI/MnNb2O6 photocatalysts by hydrothermal method.
- Antibiotics pollutants were chosen to explore the photocatalytic performance.
- The highest TC degradation activity was 87.2% within 1 h by 5%NGQDs-Bi/Mn sample.
- The enhanced activity due to the NGQDs and the p-n junction photocatalytic systems.

Novel p-n junction photocatalysts nitrogen doped graphene quantum dots (NGQDs)-BiOI/MnNb2O6 have been prepared via hydrothermal method for the environmental remediation. The photocatalytic activity of as-prepared photocatalysts was evaluated by the degradation of different antibiotics such as tetracycline (TC), oxytetracyline, ciprofloxacin and doxycycline. Compared with single MnNb2O6 and BiOI, the hybrid materials (NGQDs-BiOI/MnNb2O6) could significantly enhance photocatalytic activity. Meanwhile, both the BiOI/MnNb2O6 ratio (Bi/Mn ratio) and the amount of NGQDs displayed important influence on the antibiotics degradation. In addition, the 5%NGQDs-Bi/Mn sample performed the optimum photocatalytic degradation toward TC (87.2%) within 60 min. By further studies based on the electron spin resonance (ESR) and active species trapping experiments, this enhanced photocatalytic property could be ascribed to high charge carrier mobility of NGQDs and the p-n junction photocatalytic systems, which greatly promoted efficient separation of charge carriers.

Nitrogen doped graphene quantum dots-BiOI/MnNb2O6 p-n junction photocatalyst with enhanced visible light efficiency in photocatalytic degradation of antibiotics.137