Carbon Dots/TiO₂ hybrids for photocatalytic degradation of drugs in the water

The presented results show the synergistic effects of combining two photocatalysts (titanium oxide (TiO₂) and carbon dots (CDs)) on the enhancement of water remediation. This research involves the synthesis of fluorescent and phosphorescent carbon dots (CDs and PhCDs, respectively) and preparation of the composites, whereby they are incorporated into TiO₂ pores. Structural analysis, using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Brunauer--Emmett--Teller (BET) techniques, was conducted to assess the compositional and morphological changes resulting from CD incorporation into TiO₂.

Infrared (IR) and Raman spectroscopy allowed us to identify functional groups on the CD surface, enabling control of the optical properties of the composites. Spectroscopic studies revealed a shift in the absorption edge for the PhCDs/CDs@TiO₂ composites compared to pure TiO₂, which shows that it is possible to modulate the excitation range in the visible range. Photocatalytic activity measurements show that the PhCDs@TiO₂ composite exhibited higher activity compared to single catalysts. This enhancement is attributed to a slowdown in carrier recombination due to electron trapping in the energy band gap, leading to more efficient electron--hole separation and an increase in photocatalytic activity.

The study's results indicate that the PhCDs@TiO₂ composite has significant potential for the efficient decomposition of organic compounds in water, offering a promising solution for environmental clean-up. Additionally, the use of carbon dots opens new avenues for enhancing and modifying existing photocatalysts, paving the way for future advancements in photocatalytic applications.