Carbon-doped TiO2 coating on multiwalled carbon nanotubes with higher visible light photocatalytic activity

Carbon-doped titanium dioxide (TiO2) coating on multiwalled carbon nanotubes (MWCNTs) was prepared by oxidation of titanium carbide (TiC) coated MWCNTs. The structure, morphology and surface chemistry states of the TiO2 coating on MWCNTs were characterized by XRD, SEM, HRTEM and XPS. The results suggest that the TiO2 coated MWCNTs keep the similar morphology and length with the pristine MWCNTs. The TiO2 coating, composed of homogeneous nanosized particles, contacts closely with MWCNTs via chemistry bond and Ti-O-C bonds are found. The visible light photocatalytic activity of the prepared photocatalyst was evaluated by decomposition of methylene blue aqueous solution. A probable mechanism of TiO2 and MWCNTs on the enhancement of visible light performance is proposed. It suggests that MWCNTs play key roles, which may act as a support, absorbent, photo-generated transfer station and carbon-doping source. (C) 2011 Elsevier B.V. All rights reserved.