Porous TiO₂/Carbon Dot Nanoflowers with Enhanced Surface Areas for Improving Photocatalytic Activity

Electron–hole recombination and the narrow-range utilization of sunlight limit the photocatalytic efficiency of titanium oxide (TiO2). We synthesized carbon dots (CDs) and modified TiO2 nanoparticles (NPs) with a flower-like mesoporous structure, i.e., porous TiO2/CDs nanoflowers. Among such hybrid particles, the CDs worked as photosensitizers for the mesoporous TiO2 and enabled the resultant TiO2/CDs nanoflowers with a wide-range light absorption. Rhodamine B (Rh-B) was employed as a model organic pollutant to investigate the photocatalytic activity of the TiO2/CDs nanoflowers. The results demonstrated that the decoration of the CDs on both the TiO2 nanoflowers and the (commercially available AEROXIDE TiO2) P25 NPs enabled a significant improvement in the photocatalytic degradation efficiency compared with the pristine TiO2. The TiO2/CDs nanoflowers, with their porous structure and larger surface areas compared to P25, showed a higher efficiency to prevent local aggregation of carbon materials. All of the results revealed that the introduced CDs, with the unique mesoporous structure, large surface areas and loads of pore channels of the prepared TiO2 NPs, played important roles in the enhancement of the photocatalytic efficiency of the TiO2/CDs hybrid nanoflowers