Enhancement of carbamazepine photodegradation using hybrid of phosphorescent carbon dots coupled with highly porous TiO₂ photocatalyst

This study focuses on harnessing the synergistic effects between titanium oxide (TiO₂) and carbon dots (CDs) to enhance the photocatalytic performance of TiO₂. The work describes the synthesis of carbon dots exhibiting fluorescence (CDs) or phosphorescence (PhCDs), as well as the preparation of the TiO₂ hybrid. Structural and textural measurements (X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N₂ sorption isotherms) were conducted to elucidate the compositional and morphological changes induced by the incorporation of CDs into a matrix. Spectroscopic analyses revealed a shift of the absorption edge and range into the visible region of the CDs@TiO₂ hybrid compared with pure TiO₂. Infrared (IR) and Raman spectroscopy revealed the presence of diverse bonds associated with functional groups on the surface of the dots, enabling control over the spectroscopic properties of the resulting hybrids. Photocatalytic assessments demonstrated an enhancement in the PhCDs@TiO₂ hybrid activity compared with pure TiO₂. The proposed mechanism for the increase in photocatalytic activity in PhCDs@TiO₂ is based on the slowdown of carrier recombination, which is linked to the confinement of electrons within traps located below the conduction band. The demonstrated enhancement in photocatalytic activity holds promise for the more effective decomposition of organic compounds in water, while the utilization of carbon dots unveils new avenues for modifying existing photocatalysts.