Flame sprayed visible light-active Fe-TiO2 for photomineralisation of oxalic acid

Visible light-active Fe-doped TiO2 was prepared by a one-step flame spray pyrolysis (FSP) technique. The properties of the photocatalysts were characterised by UV–vis diffuse-reflectance spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption (BET), transmission electron microscope (TEM) and zeta potential techniques. Being a bottom-up approach, the short residence time coupled with rapid quenching during FSP resulted in homogeneous Fe-doped TiO2 for Fe/Ti ratios approximately up to 0.05. This is five times higher than that reported for particles synthesised by conventional wet techniques followed by high temperature annealing. Under visible light irradiation (λ > 400 nm), the rate of oxalic acid mineralisation by Fe-doped TiO2 (Fe/Ti = 0.05) was 6.4 times higher than that of similarly prepared bare TiO2 and Degussa P25. A unique Fe-leaching and re-adsorption properties were observed during the reaction. Unlike the system of bare TiO2 spiked with dissolved Fe(III) ions, the FSP Fe-doped TiO2 photocatalyst was found to be stable and reusable after each run with minimal loss of Fe from the surface.

[1]  Wonyong Choi,et al.  The Role of Metal Ion Dopants in Quantum-Sized TiO2: Correlation between Photoreactivity and Charge Carrier Recombination Dynamics , 1994 .

[2]  L. Mädler,et al.  Direct measurement of entrainment during nanoparticle synthesis in spray flames , 2006 .

[3]  A. Gonzalez-Elipe,et al.  Structural, Optical, and Photoelectrochemical Properties of M n + −TiO 2 Model Thin Film Photocatalysts , 2004 .

[4]  J. Araña,et al.  Role of Fe3+/Fe2+ as TiO2 dopant ions in photocatalytic degradation of carboxylic acids , 2003 .

[5]  R. Asahi,et al.  Visible-Light Photocatalysis in Nitrogen-Doped Titanium Oxides , 2001, Science.

[6]  K. Kobayakawa,et al.  Visible-light active N-doped TiO2 prepared by heating of titanium hydroxide and urea , 2005 .

[7]  Eiichi Kojima,et al.  Light-induced amphiphilic surfaces , 1997, Nature.

[8]  M. Litter,et al.  Oxalic acid destruction at high concentrations by combined heterogeneous photocatalysis and photo-Fenton processes , 2005 .

[9]  W. Maier,et al.  Visible light photodegradation of 4-chlorophenol with a coke-containing titanium dioxide photocatalyst , 2001 .

[10]  G. Low,et al.  Effects of common inorganic anions on rates of photocatalytic oxidation of organic carbon over illuminated titanium dioxide , 1990 .

[11]  P. Smirniotis,et al.  Transition Metal Modified TiO2-Loaded MCM-41 Catalysts for Visible- and UV-Light Driven Photodegradation of Aqueous Organic Pollutants , 2004 .

[12]  A. Fujishima,et al.  Electrochemical Photolysis of Water at a Semiconductor Electrode , 1972, Nature.

[13]  M. Schiavello,et al.  Structural characterization of Fe/Ti oxide photocatalysts by X-ray, ESR, and Mössbauer methods , 1985 .

[14]  M. Kosanić.  Photocatalytic degradation of oxalic acid over TiO2 power , 1998 .

[15]  Marta I. Litter,et al.  Photocatalytic properties of iron-doped titania semiconductors , 1996 .

[16]  Nick Serpone,et al.  Spectroscopic, Photoconductivity, and Photocatalytic Studies of TiO2 Colloids: Naked and with the Lattice Doped with Cr3+, Fe3+, and V5+ Cations , 1994 .

[17]  P. Boolchand,et al.  Processing of iron-doped titania powders in flame aerosol reactors , 2001 .

[18]  M. Grätzel,et al.  A low-cost, high-efficiency solar cell based on dye-sensitized colloidal TiO2 films , 1991, Nature.

[19]  Xinyong Li,et al.  Synthesis and photocatalytic oxidation properties of iron doped titanium dioxide nanosemiconductor particles , 2003 .

[20]  K. Asai,et al.  Analysis of electronic structures of 3d transition metal-doped TiO 2 based on band calculations , 2002 .

[21]  M. Anpo,et al.  Photocatalytic degradation of organic compounds diluted in water using visible light-responsive metal ion-implanted TiO2 catalysts: Fe ion-implanted TiO2 , 2003 .

[22]  B. K. Hodnett.  Photocatalytic purification and treatment of water and air : by D.F. Ollis and H. Al-Ekabi (Editors), Elsevier Science Publishers BV, Amsterdam, 1993, ISBN 0-444-89855-7, xiv + 820 pp., f450.00/$257.25 , 1994 .

[23]  A. Fujishima,et al.  Induction of cytotoxicity by photoexcited TiO2 particles. , 1992, Cancer research.

[24]  G. Colón,et al.  Synthesis, characterization and photocatalytic properties of iron-doped titania semiconductors prepared from TiO2 and iron(III) acetylacetonate , 1996 .

[25]  M. Graetzel,et al.  Visible light induced water cleavage in colloidal solutions of chromium-doped titanium dioxide particles , 1982 .

[26]  Y. Tachibana,et al.  Dye-Sensitized Nanocrystalline TiO2 Solar Cells Based on Ruthenium(II) Phenanthroline Complex Photosensitizers , 2001 .

[27]  J. Araña,et al.  Photocatalytic degradation of formic acid using Fe/TiO2 catalysts: the role of Fe3+/Fe2+ ions in the degradation mechanism , 2001 .

[28]  Kimberly A. Gray,et al.  Explaining the Enhanced Photocatalytic Activity of Degussa P25 Mixed-Phase TiO2 Using EPR , 2003 .

[29]  S. Pratsinis,et al.  Dopants in Flame Synthesis of Titania , 1995 .

[30]  M. S. Hegde,et al.  Structure and Photocatalytic Activity of Ti1-xMxO2±δ (M = W, V, Ce, Zr, Fe, and Cu) Synthesized by Solution Combustion Method , 2004 .

[31]  Kazuhito Hashimoto,et al.  Application of Photocatalytic Reactions Caused by TiO2 Film to Improve the Maintenance Factor of Lighting Systems , 1998 .

[32]  L. Mädler,et al.  Direct (one-step) synthesis of TiO2 and Pt/TiO2 nanoparticles for photocatalytic mineralisation of sucrose , 2005 .

[33]  M. Anpo.  Photocatalysis on titanium oxide catalysts: Approaches in achieving highly efficient reactions and realizing the use of visible light , 1997 .

[34]  G. Mailhot,et al.  Iron (III) aquacomplexes as effective photocatalysts for the degradation of pesticides in homogeneous aqueous solutions. , 2002, The Science of the total environment.

[35]  OhnoTeruhisa,et al.  Photocatalytic Activity of S-doped TiO2 Photocatalyst under Visible Light , 2003 .

[36]  X. Doménech,et al.  Enhanced photocatalytic degradation of maleic acid by Fe(III) adsorption onto the TiO2 surface , 2005 .

[37]  S. Pratsinis,et al.  Vapor phase synthesis of Al-doped titania powders , 1994 .

[38]  N. Ohashi,et al.  Visible-light-driven nitrogen-doped TiO2 photocatalysts: effect of nitrogen precursors on their photocatalysis for decomposition of gas-phase organic pollutants , 2005 .

[39]  H. Kisch,et al.  Daylight photocatalysis by carbon-modified titanium dioxide. , 2003, Angewandte Chemie.

[40]  Jiang Yuan,et al.  Characterization of Sol‐Gel‐Derived TiO2 Coatings and Their Photoeffects on Copper Substrates , 1995 .

[41]  R. D. Shannon.  Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides , 1976 .

[42]  W. Ingler,et al.  Efficient Photochemical Water Splitting by a Chemically Modified n-TiO2 , 2002, Science.

[43]  Jiaguo Yu,et al.  Efficient visible-light-induced photocatalytic disinfection on sulfur-doped nanocrystalline titania. , 2005, Environmental science & technology.

[44]  A. Bard,et al.  Heterogeneous photocatalytic synthesis of methane from acetic acid: new Kolbe reaction pathway , 1978 .

[45]  M. Anpo.  Preparation, Characterization, and Reactivities of Highly Functional Titanium Oxide-Based Photocatalysts Able to Operate under UV–Visible Light Irradiation: Approaches in Realizing High Efficiency in the Use of Visible Light , 2004 .

[46]  R. Grigorovici,et al.  Optical Properties and Electronic Structure of Amorphous Germanium , 1966, 1966.

[47]  M. Aguilar,et al.  Local order in titania polymorphs , 2001 .

[48]  Andrzej Michalski,et al.  The “in-flame-reaction” method for Al2O3 aerosol formation , 1977 .

[49]  H. Myers,et al.  Quantitative Analysis of Anatase-Rutile Mixtures with an X-Ray Diffractometer , 1957 .

[50]  V. Rives,et al.  Surface properties of iron-titania photocatalysts employed for 4-nitrophenol photodegradation in aqueous TiO2 dispersion , 1994 .

[51]  Lutz Mädler,et al.  Controlled synthesis of nanostructured particles by flame spray pyrolysis , 2002 .

[52]  M. Anpo,et al.  Preparation and Characterization of the Visible Light Responsive TiO2 Thin Film Photocatalysts Prepared by Magnetron Sputtering Method and Their Photocatalytic Activities for the Water Splitting Reactions , 2005 .