Heterogeneous Photocatalytic Decomposition of Phenol over TiO2 Powder

The photocatalytic decomposition of phenol in oxygenated aqueous suspensions of lightly-reduced anatase TiO2, being the most satisfactory among the semiconductors investigated from the standpoint of the photocatalytic activity and stability, has been investigated at the optimum pH 3.5. The products at the initial stage of the reaction were hydroquinone, pyrocatechol, 1,2,4-benzenetriol, pyrogallol, and 2-hydroxy-1,4-benzoquinone. These intermediates underwent further photocatalytic oxidation via acids and/or aldehydes finally into CO2 and H2O. A reaction scheme involving hydroxyl radicals as real reactive species has been proposed. Although H2O2 was formed via O2\ewdot produced by electron trapping of adsorbed oxygen, its concentration remained constant at a low value during the reaction. About 0.7 mole of O2 was consumed for the consumption of one mole of phenol at the initial stage of the reaction. These results indicated that hydroxyl radicals were formed not only via holes but also via H2O2 from O2\ew...

[1]  A. Bard,et al.  Spin trapping and electron spin resonance detection of radical intermediates in the photodecomposition of water at titanium dioxide particulate systems , 1979 .

[2]  C. A. Parker.  A new sensitive chemical actinometer. I. Some trials with potassium ferrioxalate , 1953, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.

[3]  H. Tosine,et al.  Photodechlorination of PCB's in the presence of titanium dioxide in aqueous suspensions , 1976, Bulletin of environmental contamination and toxicology.

[4]  T. Kawai,et al.  Conversion of carbohydrate into hydrogen fuel by a photocatalytic process , 1980, Nature.

[5]  D. T. Sawyer,et al.  The chemistry of superoxide ion , 1979 .

[6]  H. Yoneyama,et al.  Photocatalytic oxidation of cyanide on platinized titanium dioxide , 1980 .

[7]  B. Michael,et al.  Pulse radiolysis of benzoquinone and hydroquinone. Semiquinone formation by water elimination from trihydroxy-cyclohexadienyl radicals , 1967 .

[8]  I. Balakrishnan,et al.  MECHANISM OF REACTION OF HYDROXYL RADICALS WITH BENZENE IN THE $gamma$ RADIOLYSIS OF THE AERATED AQUEOUS BENZENE SYSTEM. , 1970 .

[9]  D. Ollis,et al.  Heterogeneous photocatalysis: Degradation of dilute solutions of dichloromethane (CH2Cl2), chloroform (CHCl3), and carbon tetrachloride (CCl4) with illuminated TiO2 photocatalyst , 1983 .

[10]  M. Fox.  Organic heterogeneous photocatalysis: chemical conversions sensitized by irradiated semiconductors , 1983 .

[11]  H. Pobiner.  Determination of Hydroperoxides in Hydrocarbon by Conversion to Hydrogen Peroxide and Measurement by Titanium Complexing , 1961 .

[12]  M. Fujihira,et al.  Heterogeneous Photocatalytic Reactions on Semiconductor Materials. III. Effect of pH and Cu2+ Ions on the Photo-Fenton Type Reaction , 1982 .

[13]  A. Fujishima,et al.  Mechanism of the Current Doubling Effect. I. The ZnO Photoanode in Aqueous Solution of Sodium Formate , 1981 .

[14]  Barry G. Oliver,et al.  Effect of suspended sediments on the photolysis of organics in water , 1979 .

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

[16]  M. Otomo.  The Spectrophotometric Determination of Titanium with Xylenol Orange , 1963 .

[17]  Heterogeneous photocatalytic and photosynthetic deposition of copper on Titanium dioxide and tungsten(VI) oxide powders , 1979 .

[18]  C. Walling.  Fenton's reagent revisited , 1975 .

[19]  H. Yoneyama,et al.  Heterogeneous photocatalytic reduction of dichromate on n-type semiconductor catalysts , 1979, Nature.

[20]  J. Herrmann,et al.  Heterogeneous photocatalysis. Oxidation of halide ions by oxygen in ultraviolet irradiated aqueous suspension of titanium dioxide , 1980 .

[21]  Allen J. Bard,et al.  Heterogeneous photocatalytic oxidation of cyanide and sulfite in aqueous solutions at semiconductor powders , 1977 .

[22]  R. Cundall,et al.  Photocatalytic oxidation of propan-2-ol in the liquid phase by rutile , 1976 .

[23]  H. Sakuragi,et al.  Semiconductor-catalyzed photooxygenation of aromatic olefins , 1980 .

[24]  E. Land,et al.  Pulse Radiolysis Investigations of Unimolecular Elimination Reactions in Free Radicals produced by OH Addition to Hydroxybenzenes , 1966, Nature.

[25]  A. Sammells,et al.  Hydrogen generation by photocatalytic oxidation of glucose by platinized n-titania powder , 1983 .

[26]  K. Hashimoto,et al.  Photocatalytic reactions of hydrocarbons and fossil fuels with water. Hydrogen production and oxidation , 1984 .

[27]  Yasunori Yamamoto,et al.  Kinetics of Heterogeneous Photocatalytic Decomposition of Phenol over Anatase TiO2 Powder , 1985 .

[28]  M. Washino,et al.  A liquid chromatographic study on the radiolysis of phenol in aqueous solution , 1979 .

[29]  P. Harvey,et al.  Photocatalytic oxidation of liquid propan-2-ol by titanium dioxide , 1983 .

[30]  M. Ward,et al.  Photocurrent enhancement via trapping of photogenerated electrons of titanium dioxide particles , 1982 .

[31]  Allen J. Bard,et al.  Heterogeneous photocatalytic oxidation of cyanide ion in aqueous solutions at titanium dioxide powder , 2002 .

[32]  A. Bard,et al.  Heterogeneous photocatalytic oxidation of hydrocarbons on platinized titanium dioxide powders , 1980 .

[33]  R. W. Matthews.  Hydroxylation reactions induced by near-ultraviolet photolysis of aqueous titanium dioxide suspensions , 1984 .

[34]  David F. Ollis,et al.  Photoassisted heterogeneous catalysis: the degradation of trichloroethylene in water , 1983 .

[35]  E. Land,et al.  Pulse radiolysis studies of aqueous phenol. Water elimination from dihydroxycyclohexadienyl radicals to form phenoxyl , 1967 .