title: Controlled fabrication of porous double-walled TiO2 nanotubes via ultraviolet-assisted anodization.
abstract: Double-walled TiO2 nanotubes with porous wall morphologies are fabricated by anodization under ultraviolet (UV) irradiation. TiO2 formed by anodization of Ti is activated to generate electrons and holes by UV and the anodization process is influenced by the photo-generated charges. As a consequence, morphologies of the fabricated TiO2 nanotubes can be adjusted by controlling the UV illumination. Double-walled TiO2 nanotubes or single-walled nanotubes can be selectively formed by switching on/off the UV illumination. The thickness of the inner and outer walls of the double-walled nanotubes can be tailored by changing the UV power. Due to their larger surface areas compared to single-walled nanotubes, the porous double-walled nanotubes exhibit an enhanced photo-degradation rate for methylene blue (MB). The mechanism of the porous double-walled TiO2 nanotubes is proposed based on the photoactive semiconducting property of the as-growing TiO2 nanotubes under UV.
authors.affiliation: Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea. socho@kaist.ac.kr.
authors.forename: Ghafar
authors.initials: G
authors.lastname: Ali
authors.forename: Hyun Jin
authors.initials: HJ
authors.lastname: Kim
authors.forename: Jae Joon
authors.initials: JJ
authors.lastname: Kim
authors.forename: Sung Oh
authors.initials: SO
authors.lastname: Cho
mesh_terms: D002384:Catalysis; D008751:Methylene Blue / Q000737:chemistry; D043942:Nanotubes / Q000737:chemistry*; D010782:Photolysis; D016062:Porosity; D014025:Titanium / Q000737:chemistry*; D014466:Ultraviolet Rays
chemical_list: C009495:titanium dioxide; D014025:Titanium; D008751:Methylene Blue