title: Visible-light-induced photoelectrochemical behaviors of Fe-modified TiO2 nanotube arrays.
abstract: Fe-modified TiO(2) nanotube arrays (TiO(2) NTs) were prepared by annealing amorphous TiO(2) NTs whose surface was covered with Fe(3+) by a dip-coating procedure, and characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and UV-visible reflectance spectroscopy. The photoelectrochemical properties were evaluated by the photocurrent response and photoelectrocatalytic (PEC) degradation of methylene orange (MO) and 4-chlorophenol in water under visible-light irradiation (λ > 420 nm). The results showed that a Fe-modified TiO(2) NTs electrode exhibited a larger photocurrent response and higher PEC activity for the degradation of organic pollutants than a pure TiO(2) NTs electrode. At a bias potential of 0.4 V, the photocurrent response of a 0.5 M Fe-modified TiO(2) NTs electrode exceeded that of a pure TiO(2) NTs electrode by a factor of about 10, and the PEC degradation rates of MO and 4-chlorophenol on a 0.5 M Fe-modified TiO(2) NTs electrode exceeded those on a pure TiO(2) NTs electrode by a factor of about 2.5. The larger photocurrent response and higher PEC activity of Fe-modified TiO(2) NTs could be attributed to the enhancement of separation of charge-carriers at the external electric field and the extension of the light response range of TiO(2) to the visible-light region with the narrowing of the band gap.
authors.affiliation: State Key Laboratory of Advanced Technology for Material Synthesis and Processing, Wuhan University of Technology, Luoshi Road 122#, Wuhan, 430070, PR China.
authors.forename: Zhihua
authors.initials: Z
authors.lastname: Xu
authors.forename: Jiaguo
authors.initials: J
authors.lastname: Yu
mesh_terms: D001391:Azo Compounds / Q000737:chemistry; D002733:Chlorophenols / Q000737:chemistry; D055664:Electrochemical Techniques; D007501:Iron / Q000737:chemistry*; D046228:Microarray Analysis / Q000295:instrumentation; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure; D055668:Photochemical Processes; D056951:Photoelectron Spectroscopy; D013056:Spectrophotometry, Ultraviolet; D014025:Titanium / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D001391:Azo Compounds; D002733:Chlorophenols; C009495:titanium dioxide; C029107:4-chlorophenol; C100258:methyl orange; D014025:Titanium; D007501:Iron