Cyclodextrine-nanoencapsulation of niclosamide: Water solubility and meaningful enhancement of visible-light—Mediated sensitized photodegradation of the drug

Photocatalytic evaluation and characterization of TiO2-riboflavin phosphate film: analysis of reactive oxygen species

The effect of Riboflavin-5'-phosphate (RFPO₄) sensitization on photocatalytic properties of TiO₂ film was studied. RFPO₄ was adsorbed on film surface to investigate the photophysical properties of TiO₂ upon blue-light photoexcitation. The film was characterized through scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, thermogravimetric analysis, and diffuse reflectance spectroscopy. The efficiency of the TiO₂/RFPO₄ film was tested for pollutant elimination in aqueous media in a visible-light-driven system. The phenol paradigmatic model was employed in an aqueous solution as a contaminant target. TiO₂/RFPO₄ sensitized photodegradation of phenol, which produces catechol, hydroquinone, and benzophenone, was monitored by absorption spectroscopy and HPLC. The results indicated that phenol degradation with TiO₂/RFPO₄ film was due to the photogeneration of two reactive oxygen species, singlet molecular oxygen (O₂(¹Δ_g)) and superoxide radical anion (O₂^·-) identified through specific detection techniques. The presence of O₂(¹Δ_g) is reported here for the first time as generated from a sensitized TiO₂ film upon visible-light photoirradiation. Based on the photophysical determinations, a photocatalytic mechanism for TiO₂/RFPO₄ was established.