title: Application of immobilized nanotubular TiO(2) electrode for photocatalytic hydrogen evolution: reduction of hexavalent chromium (Cr(VI)) in water.
abstract: In this study, immobilized TiO(2) electrode is applied to reduce toxic Cr(VI) to non-toxic Cr(III) in aqueous solution under UV irradiation. To overcome the limitation of powder TiO(2), a novel technique of immobilization based on anodization was applied and investigated under various experimental conditions. The anodization was performed at 20V-5 degrees C for 45min with 0.5% hydrofluoric acid, and then the anodized samples were annealed under oxygen stream in the range 450-850 degrees C. Based on the results of the experiments, the photocatalytic Cr(VI) reduction was favorable in acidic conditions, with approximately 98% of the Cr(VI) being reduced within 2h at pH 3. Among the samples tested under same anodizing condition, the nanotubular TiO(2) annealed at 450 and 550 degrees C showed highest reduction efficiencies of Cr(VI). In addition, the surface characterizations (zeta potential, XRD, and SEM) of these samples proved that the Cr(VI) reduction efficiency was higher under acidic conditions and at a lower annealing temperature. From this research, it was concluded that the anodized TiO(2) has the potential to be a useful technology for environmental remediation as well as photocatalytic hydrogen production from water.
authors.affiliation: Climate Change Technology Research Division, Korea Institute of Energy Research, 71-2 Jang-dong, Yuseong-gu, Daejeon 305-343, Republic of Korea.
authors.forename: Jaekyung
authors.initials: J
authors.lastname: Yoon
authors.forename: Eunjung
authors.initials: E
authors.lastname: Shim
authors.forename: Sanghyun
authors.initials: S
authors.lastname: Bae
authors.forename: Hyunku
authors.initials: H
authors.lastname: Joo
mesh_terms: D002384:Catalysis; D002623:Chemistry Techniques, Analytical / Q000379:methods; D002857:Chromium / Q000737:chemistry*; D006858:Hydrofluoric Acid / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D010777:Photochemistry / Q000379:methods; D011208:Powders; D013696:Temperature; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*; D014867:Water / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D011208:Powders; D014867:Water; D002857:Chromium; C009495:titanium dioxide; C074702:chromium hexavalent ion; D006859:Hydrogen; D014025:Titanium; D006858:Hydrofluoric Acid