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Studies on the Photoinduced Interaction between Zn(II) Porphyrin and Colloidal TiO2

DOI: 10.1155/2010/547135

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The interaction of Zn(II) porphyrin (ZnPP) with colloidal TiO2 was studied by absorption and fluorescence spectroscopy. The fluorescence emission of ZnPP was quenched by colloidal TiO2 upon excitation of its absorption band. The quenching rate constant ( ) is ?M?1?s?1. These data indicate that there is an interaction between ZnPP and colloidal TiO2 nanoparticle surface. The quenching mechanism is discussed on the basis of the quenching rate constant as well as the reduction potential of the colloidal TiO2. And the mechanism of electron transfer has been confirmed by the calculation of free energy change by applying Rehm-Weller equation as well as energy level diagram. 1. Introduction Wide-band gap semiconductor particles such as TiO2 have been widely used for different applications in photocatalysis and the environment [1, 2].Over the past decades, considerable interest has been shown in the modification of TiO2 semiconductors by organic dyes to extend the photoresponse to visible light owing to their potential application in solar energy conversion [3–5]. Dye sensitization is considered to be an efficient method to modify the photo response properties of TiO2 particles. The dyes used are erythrosine B [6], rose Bengal [7], metal porphyrin [8–10], and so forth. Porphyrins, (including metal-free porphyrins, metalloporphyrins and supramolecular porphyrins) [11] are recognized to be the most promising sensitizers [12]. The chemistry of porphyrin derivatives has played an important role especially during the past decade in particular branches of new materials science, and many researchers have undertaken projects on the synthesis of variously substituted compounds to obtain new functional materials [13–15]. Metalloporphyrin may be an appropriate candidate because of its high absorption coefficient within the solar spectrum and its good chemical stability in comparison to that of other dyes. They are highly effective photocatalysts due to their very strong absorption in the 400?nm–450?nm region (Soret band) and in the 500?nm–700?nm region (Q-bands) and, in fact, the presence of p-electrons affords the condition for electron transfer during the photoreaction. In the present work we have investigated the electron transfer from excited ZnPP (see Scheme 1) to the conduction band of TiO2 colloid by using absorption and fluorescence spectroscopy. Scheme 1: Structure of ZnPP. 2. Materials and Methods 2.1. Materials Zn(II) porphyrin and tetrabutyl titanate were purchased from Aldrich. The doubly distilled water was used for preparing the solutions. All measurements

References

[1]  M. R. Hoffmann, S. T. Martin, W. Choi, and D. W. Bahnemann, “Environmental applications of semiconductor photocatalysis,” Chemical Reviews, vol. 95, no. 1, pp. 69–78, 1995.
[2]  M. Muruganandham and M. Swaminathan, “Photocatalytic decolourisation and degradation of Reactive Orange 4 by Ti -UV process,” Dyes and Pigments, vol. 68, no. 2-3, pp. 133–141, 2006.
[3]  J. He, F. Chen, J. Zhao, and H. Hidaka, “Adsorption model of ethyl ester of fluorescein on colloidal Ti and the mechanism of the interfacial electron transfer,” Colloids and Surfaces A, vol. 142, no. 1, pp. 49–57, 1998.
[4]  A. Kathiravan and R. Renganathan, “An investigation on electron transfer quenching of zinc(II) meso-tetraphenylporphyrin (ZnTPP) by colloidal Ti ,” Spectrochimica Acta A, vol. 71, no. 3, pp. 1106–1111, 2008.
[5]  A. Kathiravan, V. Anbazhagan, M. Asha Jhonsi, and R. Renganathan, “Fluorescence quenching of meso-tetrakis (4-sulfonatophenyl) porphyrin by colloidal Ti ,” Spectrochimica Acta A, vol. 70, no. 3, pp. 615–623, 2008.
[6]  P. V. Kamat and M. A. Fox, “Photosensitization of Ti colloids by Erythrosin B in acetonitrile,” Chemical Physics Letters, vol. 102, no. 4, pp. 379–390, 1983.
[7]  H. Ross, J. Bendig, and S. Hecht, “Sensitized photocatalytical oxidation of terbutylazine,” Solar Energy Materials and Solar Cells, vol. 33, no. 4, pp. 475–483, 1994.
[8]  G. Mele, G. Ciccarella, G. Vasapollo, E. García-López, L. Palmisano, and M. Schiavello, “Photocatalytic degradation of 4-nitrophenol in aqueous suspension by using polycrystalline Ti samples impregnated with Cu(II)-phthalocyanine,” Applied Catalysis B, vol. 38, no. 4, pp. 309–311, 2002.
[9]  G. Mele, R. Del Sole, G. Vasapollo, E. García-López, L. Palmisano, and M. Schiavello, “Photocatalytic degradation of 4-nitrophenol in aqueous suspension by using polycrystalline Ti impregnated with functionalized Cu(II) -porphyrin or Cu(II)-phthalocyanine,” Journal of Catalysis, vol. 217, no. 2, pp. 334–346, 2003.
[10]  G. Mele, R. Del Sole, and G. Vasapollo, “Polycrystalline Ti impregnated with cardanol-based porphyrins for the photocatalytic degradation of 4-nitrophenol,” Green Chemistry, vol. 6, no. 12, pp. 604–616, 2004.
[11]  S. Cho, W.-S. Li, M.-C. Yoon et al., “Relationship between incoherent excitation energy migration processes and molecular structures in zinc(II) porphyrin dendrimers,” Chemistry, vol. 12, no. 29, pp. 7576–7583, 2006.
[12]  M. Unno, T. Matsui, and M. Ikeda-Saito, “Structure and catalytic mechanism of heme oxygenase,” Natural Product Reports, vol. 24, no. 3, pp. 553–558, 2007.
[13]  R. Harada, Y. Matsuda, H. Okawa, and T. Kojima, “A porphyrin nanotube: size-selective inclusion of tetranuclear molybdenum-oxo clusters,” Angewandte Chemie, vol. 43, no. 14, pp. 1825–1831, 2004.
[14]  T. S. Balaban, “Tailoring porphyrins and chlorins for self-assembly in biomimetic artificial antenna systems,” Accounts of Chemical Research, vol. 38, no. 8, pp. 612–619, 2005.
[15]  Y. Cho, W. Choi, C.-H. Lee, T. Hyeon, and H.-I. Lee, “Visible light-induced degradation of carbon tetrachloride on dye-sensitized Ti ,” Environmental Science and Technology, vol. 35, no. 5, pp. 966–973, 2001.
[16]  P. V. Kamat, J.-P. Chauvet, and R. W. Fessenden, “Photoelectrochemistry in particulate systems. 4. Photosensitization of a Ti semiconductor with a chlorophyll analogue,” Journal of Physical Chemistry, vol. 90, no. 7, pp. 1389–1395, 1986.
[17]  K. Hasegawa and T. Noguchi, “Density functional theory calculations on the dielectric constant dependence of the oxidation potential of chlorophyll: implication for the high potential of P680 in photosystem II,” Biochemistry, vol. 44, no. 24, pp. 8865–8872, 2005.
[18]  E. J. Shin and D. Kim, “Substituent effect on the fluorescence quenching of various tetraphenylporphyrins by ruthenium tris(2, -bipyridine) complex,” Journal of Photochemistry and Photobiology A, vol. 152, no. 1–3, pp. 25–31, 2002.
[19]  S. L. Murov, I. Carmichael, and G. L. Hug, Handbook of Photochemistry, Marcel-Dekker, New York, NY, USA, 2nd edition, 1993.
[20]  D. Rehm and A. Weller, “Kinetics of fluorescence quenching by electron and hydrogen-atom transfer,” Israel Journal of Chemistry, vol. 8, pp. 259–265, 1970.
[21]  S. Parret, F. Morlet-Savary, J. P. Fouassier, and P. Ramamurthy, “Spin-orbit-coupling-induced triplet formation of triphenylpyrylium ion: a flash photolysis study,” Journal of Photochemistry and Photobiology A, vol. 83, no. 3, pp. 205–312, 1994.
[22]  S. L. Murov, I. Carmichael, and G.L. Hug, Handbook of Photochemistry, Marcel-Dekker, New York, NY, USA, 2nd edition, 1993.
[23]  Q. Dai and J. Rabani, “Photosensitization of nanocrystalline Ti films by anthocyanin dyes,” Journal of Photochemistry and Photobiology A, vol. 148, no. 1–3, pp. 17–23, 2002.

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