Synthesis of a solar photo and bioactive CNT–TiO2 nanocatalyst

Abstract

A novel route for the synthesis of CNT–TiO₂ hybrid nanostructures is reported based on a combination of sol–gel and arc discharge methods in a liquid. The CNT–TiO₂ nanocomposites were prepared using an arc discharge between graphitic electrodes in a TiO₂ solution and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and ultra violet–visible absorption spectroscopy (UV–Vis). The photocatalytic performance in visible light and antibacterial activity of the CNT–TiO₂ nanocomposites demonstrated degradation of Rhodamine B (Rh. B) and inactivation of Escherichia coli (E. coli) bacteria. It was observed that the absorption spectrum of the CNT–TiO₂ nanocomposites extended into the visible region, and considerably improved photocatalytic efficiency and antibacterial properties under visible light irradiation. The amount of CNTs formed in the TiO₂ solution was controlled by the arc duration time and the optimum value for the best possible photocatalytic performance of each specific arc current was also probed. We found that the prepared samples have high photocatalytic activity and antibacterial efficiency. The significant enhancement in the photocatalytic properties and antibacterial activity of CNT–TiO₂ nanocomposites under visible light irradiation can be attributed to the effect of doped CNTs acting as electron traps in the TiO₂ band gap.