Preparation and photocatalytic ability of highly defective carbon nanotubes

The highly defective carbon nanotubes (CNTs) were prepared using a heat-treatment technique and their photocatalytic ability was reported for the first time. The results showed that the highly defective CNTs had the photocatalytic ability in the range of visible light. The results also indicated that the electrical properties of CNTs were dependent not only on the diameter and helicity but also on the defect number of tubes. The defects of CNTs might be produced from vacancies, local lattice reordering and intertube reorientation during the course of the desorption of oxygen atoms, which could initiate defect states in the band gap. Absorption of visible light led to the formation of electron/hole pairs and hence caused photocatalytic oxidation. Consequently, the highly defective CNTs having the photocatalytic ability would be promising as a new photocatalytic material in the visible light. (C) 2009 Elsevier Inc. All rights reserved.