Preparation of the heterojunction catalyst N-doping carbon quantum dots/P25 and its visible light photocatalytic activity.

N-doping carbon quantum dots were successfully loaded on P25 nanoparticles (denoted as N-CDs/P25) by facile hydrothermal process, and their morphology and chemical structure were systematically studied. The carrier of N-CDs can significantly broaden the photoresponse range of the P25 to the visible region, accelerate charge transportation and separation. Application of the N-CDs/P25 material for the photocatalytic decomposition of Rhodamine B (RhB) gave improved activity relative to P25. The best degradation activity obtained at 6mL N-CDs/P25 under visible light irradiation, which shows a 13.06 fold photocatalytic activity over P25. Radical trapping control experiment and Electron Paramagnetic Resonance (EPR) measurements have been applied to explore the photodegradation dynamic and visible-light driven degradation mechanism. This work provides new insights into the fabrication of N-doping carbon quantum dots/TiO2 composite and is promising to open new possibilities in the application of carbon-TiO2 composites as the photocatalysts in the environmental protection issues.