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.