Surface carbon layer and visible-light photocatalytic activities of carbon-coated TiO 2 nanotubes synthesized in organic electrolytes

Abstract

TiO 2 nanotubes (NTs) are synthesized by anodization of a titanium foil in organic electrolytes, followed by thermal treatment in O 2 at different temperatures. These TiO 2 NTs exhibit visible-light photocatalytic activity which strongly depends on the formation of the thin surface carbon layer induced by dissociation of the electrolytes. Microstructural and spectral examinations suggest that the presence of the thin carbon layer and improved TiO 2 crystallinity achieved by annealing at a higher temperature conjointly lead to the enhanced photocatalytic activity. Our results disclose that the visible photocatalytic activity of TiO 2 NTs can be enhanced by using the appropriate electrolytes and thermal treatment conditions. © 2011 Springer-Verlag.