Graphitized Carbon Nanotubes Formed in TiO₂ Nanotube Arrays: A Novel Functional Material with Tube-in-Tube Nanostructure

Carbon nanotubes with high orientation and low graphitization formed in TiO 2 nanotube arrays were fabricated by annealing the latter in carbon atmosphere, constructing a novel functional material with tube-in-tube nanostructure. Compared with unmodified TiO 2, coupled C−TiO 2 photocatalyst shows an enhanced efficiency of photodecomposing methyl orange process due to the increasing carrier rate and stronger adsorbability as well as the unique mechanical nanostructure. Furthermore, the transition from anatase to rutile was suppressed by carbon, resulting in a high content of the photoactive anatase, which also benefits the high catalytic activity of C−TiO 2 photocatalyst.