Highly active TiO2−x−yNxFy visible photocatalyst prepared under supercritical conditions in NH4F/EtOH fluid

A novel N and F co-doped TiO2 (TiO2−x−yNxFy) photocatalyst is prepared by treating the TiO2 precursor in NH4F/ethanol fluid under supercritical conditions. During photocatalytic degradation of methylene blue under visible light irradiation, the as-prepared TiO2−x−yNxFy exhibits higher activity than the undoped TiO2, N-doped TiO2 (TiO2−xNx), and F-doped TiO2 (TiO2−yFy). Based on the characterizations including XRD, Raman, FTIR, TEM, PLS, UV–vis DRS, N2 adsorption–desorption isotherms, XPS and NH3-TPD, the synergetic promotions of N- and F-dopants incorporated into the TiO2 lattice are discussed based on the enhanced spectral response in visible region, oxygen vacancies, and surface acidic sites. Meanwhile, the supercritical treatment also promotes the activity owing to the increase in both the surface area and the crystallization degree of anatase, and the enhanced incorporation of N- and F-dopants into the TiO2 lattice.

[1]  F. Saito,et al.  Raman spectroscopic analysis of sulphur-doped TiO2 by co-grinding with TiS2 , 2007 .

[2]  A. Fujishima,et al.  Anatase TiO2 nanoparticles on rutile TiO2 nanorods: a heterogeneous nanostructure via layer-by-layer assembly. , 2007, Langmuir.

[3]  J. Yao,et al.  Great enhancement of photocatalytic activity of nitrogen-doped titania by coupling with tungsten oxide. , 2006, The journal of physical chemistry. B.

[4]  W. Choi,et al.  Enhanced remote photocatalytic oxidation on surface-fluorinated TiO2. , 2004, Langmuir : the ACS journal of surfaces and colloids.

[5]  Hajime Haneda,et al.  Visible-Light-Driven N−F−Codoped TiO2 Photocatalysts. 1. Synthesis by Spray Pyrolysis and Surface Characterization , 2005 .

[6]  C. Burda,et al.  Photoelectron Spectroscopic Investigation of Nitrogen-Doped Titania Nanoparticles , 2004 .

[7]  Annabella Selloni,et al.  Characterization of paramagnetic species in N-doped TiO2 powders by EPR spectroscopy and DFT calculations. , 2005, The journal of physical chemistry. B.

[8]  Yoshimi Tanaka,et al.  Effects of Heat Treatment on Photocatalytic Property of Sol-Gel Derived Polycrystalline TiO2 , 2001 .

[9]  Hyunwoong Park,et al.  Effects of TiO2 Surface Fluorination on Photocatalytic Reactions and Photoelectrochemical Behaviors , 2004 .

[10]  Gaorong Han,et al.  Investigation of structure and properties of N-doped TiO2 thin films grown by APCVD , 2006 .

[11]  Cyril Aymonier,et al.  Review of supercritical fluids in inorganic materials science , 2006 .

[12]  A. Gonzalez-Elipe,et al.  Effect of Visible and UV Illumination on the Water Contact Angle of TiO2 Thin Films with Incorporated Nitrogen , 2007 .

[13]  Masaaki Kitano,et al.  Recent developments in titanium oxide-based photocatalysts , 2007 .

[14]  C. Real,et al.  Photo-induced Transformation, upon UV Illumination in Air, of Hyponitrite SpeciesN2O22- Preadsorbed onTiO2 Surface , 1996 .

[15]  Yuka Watanabe,et al.  Nitrogen-Concentration Dependence on Photocatalytic Activity of TiO2-xNx Powders , 2003 .

[16]  W. Ho,et al.  Low-temperature hydrothermal synthesis of S-doped TiO2 with visible light photocatalytic activity , 2006 .

[17]  K. Nakamoto.  Infrared spectra of inorganic and coordination compounds , 1970 .

[18]  Lothar Frey,et al.  Ion Implantation and Annealing for an Efficient N-Doping of TiO2 Nanotubes , 2006 .

[19]  J. Yao,et al.  Synthesis and Characterization of Titania Prepared by Using a Photoassisted Sol−Gel Method , 2003 .

[20]  V. Nadtochenko,et al.  Preparation, testing and characterization of doped TiO2 active in the peroxidation of biomolecules under visible light. , 2005, The journal of physical chemistry. B.

[21]  Baibiao Huang,et al.  Study of the Nitrogen Concentration Influence on N-Doped TiO2Anatase from First-Principles Calculations , 2007 .

[22]  J. Bocquet,et al.  Modeling of a continuous reactor for TiO2 powder synthesis in a supercritical fluid — experimental validation , 1996 .

[23]  C. Lamberti,et al.  Oriented TiO2 Nanostructured Pillar Arrays: Synthesis and Characterization , 2008 .

[24]  P. Sherwood,et al.  Studies of Carbon Nanotubes and Fluorinated Nanotubes by X-ray and Ultraviolet Photoelectron Spectroscopy , 2004 .

[25]  Jinlong Zhang,et al.  Preparation, Photocatalytic Activity, and Mechanism of Nano-TiO2 Co-Doped with Nitrogen and Iron (III) , 2007 .

[26]  Hexing Li,et al.  Highly active TiO2N photocatalysts prepared by treating TiO2 precursors in NH3/ethanol fluid under supercritical conditions. , 2006, The journal of physical chemistry. B.

[27]  Yi-Chun Jin,et al.  Highly Active TiO2-xNx Visible Photocatalyst Prepared by N-Doping in Et3N/EtOH Fluid under Supercritical Conditions , 2008 .

[28]  A. Bard,et al.  Novel carbon-doped TiO2 nanotube arrays with high aspect ratios for efficient solar water splitting. , 2006, Nano letters.

[29]  Miguel Pelaez,et al.  Mesoporous nitrogen-doped TiO2 for the photocatalytic destruction of the cyanobacterial toxin microcystin-LR under visible light irradiation. , 2007, Environmental science & technology.

[30]  K. Warrier,et al.  Structural Modifications and Associated Properties of Lanthanum Oxide Doped Sol−Gel Nanosized Titanium Oxide , 2002 .

[31]  J. Yates,et al.  The Effect of Nitrogen Ion Implantation on the Photoactivity of TiO2 Rutile Single Crystals , 2004 .

[32]  L. Gao,et al.  Synthesis, characterization, and optical properties of well-defined N-doped, hollow silica/titania hybrid microspheres. , 2007, Langmuir : the ACS journal of surfaces and colloids.

[33]  M. Hoffmann,et al.  Oxidative Power of Nitrogen-Doped TiO2 Photocatalysts under Visible Illumination , 2004 .

[34]  Toshinori Mori,et al.  Preparation of visible-light-responsive TiO2-xNx photocatalyst by a sol-gel method: analysis of the active center on TiO2 that reacts with NH3. , 2005, Langmuir : the ACS journal of surfaces and colloids.

[35]  H. Freund,et al.  Photochemistry on metal nanoparticles. , 2006, Chemical reviews.

[36]  Guohua Chen,et al.  Fabrication of Boron-Doped TiO2 Nanotube Array Electrode and Investigation of Its Photoelectrochemical Capability , 2007 .

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

[38]  Jimmy C. Yu.  Effects of acidic and basic hydrolysis catalysts on the photocatalytic activity and microstructures of bimodal mesoporous titania , 2003 .

[39]  G. Busca,et al.  FT-IR characterization of the surface acidity of different titanium dioxide anatase preparations , 1985 .

[40]  Ching-Yuan Chang,et al.  Effect of Plasma Processing Gas Composition on the Nitrogen-Doping Status and Visible Light Photocatalysis of TiO2 , 2007 .

[41]  Y. Jung,et al.  Size effects in the Raman spectra of TiO2 nanoparticles , 2005 .

[42]  Francis Levy,et al.  Photoluminescence in TiO2 anatase single crystals , 1993 .

[43]  John T Yates,et al.  Surface science studies of the photoactivation of TiO2--new photochemical processes. , 2006, Chemical reviews.

[44]  Wanhong Ma,et al.  Preparation of titania/carbon nanotube composites using supercritical ethanol and their photocatalytic activity for phenol degradation under visible light irradiation , 2007 .

[45]  F. Tian,et al.  DFT description on electronic structure and optical absorption properties of anionic S-doped anatase TiO2. , 2006, The journal of physical chemistry. B.

[46]  Aicheng Chen,et al.  Synthesis and Characterization of Carbon-Doped TiO 2 Nanostructures with Enhanced Visible Light Response , 2007 .

[47]  Xianzhi Fu,et al.  The effect of postnitridation annealing on the surface property and photocatalytic performance of N-doped TiO2 under visible light irradiation , 2008 .

[48]  Hajime Haneda,et al.  Fluorine-doped TiO2 powders prepared by spray pyrolysis and their improved photocatalytic activity for decomposition of gas-phase acetaldehyde , 2005 .

[49]  M. Anpo,et al.  Preparation of nitrogen-substituted TiO2 thin film photocatalysts by the radio frequency magnetron sputtering deposition method and their photocatalytic reactivity under visible light irradiation. , 2006, The journal of physical chemistry. B.

[50]  Balasubramanian Viswanathan,et al.  Synthesis, Characterization, Electronic Structure, and Photocatalytic Activity of Nitrogen-Doped TiO2 Nanocatalyst , 2005 .

[51]  H. Kisch,et al.  Visible light activity and photoelectrochemical properties of nitrogen-doped TiO2 , 2004 .

[52]  Yi-Chun Jin,et al.  Highly active La2O3/Ti1−xBxO2 visible light photocatalysts prepared under supercritical conditions , 2008 .

[53]  K. Zhu,et al.  Size and phonon-confinement effects on low-frequency Raman mode of anatase TiO2 nanocrystal , 2005 .

[54]  K. Watari,et al.  Silica-doped alumina cryogels with high thermal stability , 2007 .

[55]  V. Buznik,et al.  IR Spectroscopic Study of the Structure of Glasses Based on Titanium Oxyfluoride , 2004 .

[56]  Z. Zou,et al.  Low temperature preparation and visible light photocatalytic activity of mesoporous carbon-doped crystalline TiO2 , 2007 .

[57]  S. Morrison.  Surface states associated with acid sites on solids , 1975 .

[58]  Xinyu Zhang,et al.  Supercritical preparation of a highly active S-doped TiO2 photocatalyst for methylene blue mineralization. , 2007, Environmental science & technology.

[59]  H. Tada,et al.  Photoreactivity of Sol−Gel TiO2 Films Formed on Soda-Lime Glass Substrates: Effect of SiO2 Underlayer Containing Fluorine , 1999 .

[60]  K. Abe,et al.  Photoacoustic and photoluminescence characterization of highly porous, polycrystalline TiO2 electrodes made by chemical synthesis , 2000 .

[61]  Harland G. Tompkins,et al.  Titanium nitride oxidation chemistry: An x‐ray photoelectron spectroscopy study , 1992 .