Preparation of Carbon‐Nanotube‐supported TiO2 for Enhanced Dye‐degrading Photocatalytic Activity

Abstract

Titanium dioxide–carbon nanotube (TiO2‐CNT) nanocomposites were successfully synthesized by a sol–gel method. The prepared TiO2‐CNT samples were characterized by transmission electron microscopy (TEM), X‐ray photoelectron spectroscopy (XPS), and X‐ray diffraction (XRD). The photocatalytic activity of the samples was tested by photodegradation of methylene blue (MB) and methyl orange (MO) in aqueous solution under UV‐light irradiation. In the photocatalytic results, the TiO2‐CNTs, as compared to the pristine TiO2 and commercial P25 TiO2 photocatalysts, exhibited the fastest degradation performance in both dye solutions. The TiO2‐CNTs’ apparent rate constants were 0.0232 and 0.0214 min–1 in the MB and MO solutions, respectively, both of which are approximately 5 times greater than that for the commercial P25 TiO2 (MB: 0.0046 min–1, MO: 0.0043 min–1). And as for the estimated electron‐transfer resistance (Rct) results from the ac impedance spectra, the values increased in the following order: TiO2‐CNT < P25 TiO2 < pristine TiO2 , indicating that CNTs can serve as electron‐transmitting paths, thus suppressing the recombination rate of photogenerated electron/hole pairs. Moreover, the degree of photodegradation inhibition was insignificant in the presence of interfering anion species (1000‐fold).