WANG Qing, SHANG Jing*, ZHAO Feng-wei, LI Jing, HE Song-jie

(State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China)

Abstract: Multi-walled carbon nanotubes (MWCNTs) and TiO₂ composite catalysts device — ITO/MWCNTs-TiO₂/ITO, was prepared by a sol–gel method over indium tin oxide (ITO) substrate. The surface morphology and properties of devices were characterized by SEM, XPS and UV-Vis spectra. We employed photocatalytic degradation of rhodamine B (RhB) under visible light irradiation as the probe reaction to evaluate its photocatalytic activity. The XPS spectra indicated that Ti-C structures did not form between MWCNTs and TiO₂. The linear scan voltammograms (I-V curves) showed that the ITO/MWCNTs-TiO₂/ITO exhibited better photoresponse of visible light than the blank device ITO/TiO₂/ITO. For photocatalytic degradation of RhB under visible light irradiation, ITO/MWCNTs-TiO₂/ITO exhibited fine activity, presented 4.2 times of the ITO/TiO₂/ITO. The MWCNTs did not substitute O ions in the TiO₂ lattice, but served as a photosensitizer. The MWCNTs could be excited under visible light, and the photogenerated electrons transferred to the conduction band of TiO₂, via a series of reactions, degradated RhB ultimately.

Key words: Titanium dioxide; Multi-wall carbon nanotubes; Visible-light; Photocatalysis; Rhodamine B

E-mail: shangjing@pku.edu.cn

Journal of Molecular Catalysis, Vol. 24, Issue 6, 2010, 537~541