Photocatalytic degradation of ofloxacin in water assisted by TiO2 nanowires on carbon cloth: contributions of H2O2 addition and substrate absorbability.

Abstract

Vertically aligned TiO₂ nanowires demonstrate exceptional photoactivity owing to their high specific surface area and improved charge separation; however, their unsatisfactory interaction with target contaminants diminishes photocatalytic degradation efficiency in water. Here, we present a mild solution method to precipitate anatase TiO₂ nanowire arrays, measuring 1.5 μm in thickness, over carbon cloth to ensure substantial interactions with target pollutants and, in turn, a superior photoactivity. Compared to TiO₂ nanowire arrays grown on metallic Ti substrates, TiO₂ nanowires supported on carbon cloth substrates demonstrate markedly superior efficiency in the photocatalytic degradation of ofloxacin (OFL) molecules in water when exposed to UV light. The TiO₂ nanowires remove 90-97% OFL in water with a high initial concentration of 50 ppm in 6 h under UV light irradiation for up to six cycles. The contributions of the hydrogen peroxide (H₂O₂) additive were also studied. An enhanced efficiency could be achieved only when the H₂O₂ in water reaches a critical amount, below which a negative effect is noted. This investigation demonstrates the potential of improving the photoactivity of one-dimensional TiO₂ nanostructures by utilizing a highly adsorptive substrate, which can help mitigate the effects of hazardous materials in water.