Fabrication of a TiO2/carbon nanowall heterojunction and its photocatalytic ability

A two-dimensional TiO2/carbon nanowall composite material was fabricated by growing carbon nanowalls on a Ti sheet with hot filament chemical vapor deposition, followed by metal-organic chemical vapor deposition using titanium isopropoxide as TiO2 precursor and argon as carrier gas. Scanning electron microscopy showed that TiO2 was uniformly coated on the entire carbon nanowall and a TiO2/carbon nanowall composite was obtained. Raman spectroscopy and X-ray diffraction indicated that the crystal phase of the TiO2 coating was anatase. The asymmetry of the current-voltage plot for the material revealed that a heterojunction was formed between the TiO2 and the carbon nanowall. As a result of this heterojunction, enhanced separation of photogenerated electrons and holes was confirmed by surface photovoltage and photocurrent measurements. The investigation of photocatalytic ability showed that the TiO2/carbon nanowall had a higher photocatalytic activity than TiO2 nanotubes for the degradation of phenol under UV light irradiation. (C) 2008 Elsevier Ltd. All rights reserved.