Preparation of titania/carbon nanotube composites using supercritical ethanol and their photocatalytic activity for phenol degradation under visible light irradiation

Titanium dioxide (anatase, TiO2) nanoparticles have been successfully deposited onto multi-walled carbon nanotubes (MWCNTs) via hydrolysis of titanium isopropoxide in supercritical ethanol. The as-prepared composites were characterized by X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. It was demonstrated that the MWCNTs were decorated with well-dispersed anatase nanoparticles less than 7 nm in diameter. The size and loading content of the nanoparticles on MWCNTs could be tuned by manipulating the ratio of precursor to MWCNTs, and the formation mechanism of the composites was also discussed. The absorbance spectrum of the resultant TiO2/MWCNT composites extended to the whole UV–visible region due to the decoration of TiO2 on MWCNTs. The TiO2/MWCNT composites were used as photocatalyst for phenol degradation under irradiation of visible light, which showed higher efficiency compared to a mixture of TiO2 and MWCNTs.