Photocatalytic Hydrogen Production on Nanocomposite of Carbon Nanotubes and TiO₂

Sonochemical/hydration–dehydration techniques were used to synthesize binary composites CNT/TiO₂ consisting single wall carbon nanotubes (SWNTs) and multiwall carbon nanotubes (MWNTs) with TiO₂. Different percentages of CNT/TiO₂ were prepared (0.25, 0.5, and 1%). The morphological and physiochemical properties were investigated by powder X-ray diffraction (XRD), Raman spectroscopy and UV–vis diffuse reflectance spectroscopy. It was found the TiO₂ nanoparticles were more homogenized with SWNTs compared with MWNTs. 7.5% methanol solution was used as a sacrificial agent to produce hydrogen gas with 65 mg of synthesized binary composites at light intensity 40 mW cm⁻². The results show that SWNTs increased the activity of TiO₂ more than for MWNTs. The hydrogen production shows higher activity for TiO₂ with lower ratio of SWNTs, while the activity was raised for TiO₂ with increasing ratio of MWNTs. (paper)