Multiwalled Carbon Nanotube-TiO2 Nanocomposite for Visible-Light-Induced Photocatalytic Hydrogen Evolution

Multiwalled carbon nanotube-(MWCNT-) TiO2 nanocomposite was synthesized via hydrothermal process and characterized by X-ray diffraction, UV-vis diffuse reflectance spectroscopy, field emission scanning electron microscope, thermogravimetry analysis, and N-2 adsorption-desorption isotherms. Appropriate pretreatment on MWCNTs could generate oxygen-containing groups, which is beneficial for forming intimate contact between MWCNTs and TiO2 and leads to a higher thermal stability of MWCNT-TiO2 nanocomposite. Modification with MWCNTs can extend the visible-light absorption of TiO2. 5wt% MWCNT-TiO2 derived from hydrothermal treatment at 140 degrees C exhibiting the highest hydrogen generation rate of 15.1 mu mol.h(-1) under visible-light irradiation and a wide photoresponse range from 350 to 475 nm with moderate quantum efficiency (4.4% at 420 nm and 3.7% at 475 nm). The above experimental results indicate that the MWCNT-TiO2 nanocomposite is a promising photocatalyst with good stability and visible-light-induced photoactivity.