Effect of Carbon Nanotubes and Carbon Nanotubes/Gold Nanoparticles Composite on the Photocatalytic Activity of TiO2 and TiO2‐SiO2

A carbon nanotube (CNT)/gold nanoparticle (NP) nanocomposite was synthesized by simultaneously reducing the Au ions and depositing Au NPs on the surface of a CNT. The functional groups were investigated with Fourier transform infrared spectra. From the Raman spectra, the D‐band and G‐band of the CNT were identified. The deposition of nanometer‐sized Au NPs on the CNT sites was observed by transmission electron microscopy. The photodegradation of methylene blue (MB) in aqueous solutions was studied using various photocatalysts, including TiO2, TiO2‐SiO2, CNT/TiO2, CNT/TiO2‐SiO2, Au/TiO2, CNT‐Au/TiO2, and CNT‐Au/TiO2‐SiO2 composites. CNT addition leads to a synergic effect, improving the photoactivity of the catalysts. A possible physically based mechanism was proposed involving the reduction of electron‐hole recombination and fast electron‐transfer possibility.