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Abstract:

Initial quantum yields φ for the formation of DMPO-OH adducts in clear, aerated, unbuffered TiO2 sols irradiated at 295 nm were determined by kinetic electron paramagnetic resonance spectrometry as function of the 5,5-dimethyl-1-pyrroline N-oxide (DMPO) spin trap concentration, photon irradiance Io, and added dichlorobenzene DCB, at 298 K. φ steadily increases with [DMPO] in the range 0.3 mM to 0.3 M, extrapolating to φ[DMPO]→∞ = 0.54 ± 0.10, in contrast with the constant yields obtained for the homogeneous generation of OH radicals in the photodissociation of H2O2 at 254 nm under similar conditions. In TiO2 sols at [DMPO] = 0.6 mM, φ (≈0.002) remains constant over a 20-fold variation of Io, but decreases upon addition of comparable DCB concentrations. These observations prove that (1) DMPO reacts with photogenerated holes and/or OH radicals on the surface of TiO2 particles rather than in the solution bulk, (2) it is possible to approach quantitative carrier trapping, (3) DCB is as reactive as DMPO toward some of the photogenerated carriers and (4) the recombination of a single carrier pair - the usual event in small particles at moderate photon fluxes - is a pseudo-first-order process. Photocatalysis in semiconductor sols is a stochastic process not amenable to conventional kinetic analysis based on rate expressions involving continuous concentration variables. Quantum yields are largely controlled by the anodic (h + D → D+), rather than by the slower (e + O2 → O2•-) cathodic charge transfer reaction. © 1996 American Chemical Society.

Registro:

Documento: Artículo
Título:Quantitative spin-trapping studies of weakly illuminated titanium dioxide sols. Implications for the mechanism of photocatalysis
Autor:Grela, M.A.; Coronel, M.E.J.; Colussi, A.J.
Filiación:Department of Chemistry, University of Mar del Plata, 7600 Mar del Plata, Argentina
Department of Physical Chemistry, Faculty of Exact and Natural Sciences, University of Buenos Aires, 1428 Buenos Aires, Argentina
Año:1996
Volumen:100
Número:42
Página de inicio:16940
Página de fin:16946
DOI: http://dx.doi.org/10.1021/jp953562r
Título revista:Journal of Physical Chemistry
ISSN:00223654
Registro:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00223654_v100_n42_p16940_Grela

Referencias:

  • Linsebigler, A.L., Guansquan, L., Yates, J.T., (1995) Chem. Rev., 95, p. 735
  • Hoffmann, M.R., Martin, S.T., Choi, W., Bahnemann, D.W., (1995) Chem. Rev., 95, p. 69
  • Serpone, N., (1994) Res. Chem. Intermed., 20, p. 953
  • Fox, M.A., Dulay, M.T., (1993) Chem. Rev., 93, p. 341
  • (1993) Photocatalytic Purification of Waler and Air, , Ollis, D. F.; Al-Ekabi, H., Eds.; Elsevier: Amsterdam
  • (1989) Photocatalysis: Fundamentals and Applications, , Serpone, N.; Pelizzetti, E., Eds.; Wiley: New York
  • Fujishima, A., Honda, K., (1972) Nature, 37, p. 238
  • Parmon, V. N.; Zamaraev, K. I. In reference 6, p 565; Ross, R.T., (1966) J. Chem. Phys., 45, p. 1
  • Ross, R.T., Hsiao, T.-L., (1977) J. Appl. Phys., 48, p. 4783
  • Kamat, P.V., (1993) Chem. Rev., 93, p. 267
  • Vinodsopal, K., Bedja, I., Hotchandani, S., Kamat, P.V., (1994) Langmuir, 10, p. 1767
  • Gerischer, H., Heller, A., (1991) J. Phys. Chem., 95, p. 5261
  • Gerischer, H., (1991) J. Phys. Chem., 95, p. 1356
  • Gerischer, H. In reference 5, p 1; Fox, M. A. In reference 5, p 163; Serpone, N.; Pelizzetti, E.; Hidaka, H. In reference 5, p 225; Lawless, D., Serpone, N., Meisel, D., (1991) J. Phys. Chem., 95, p. 5166
  • Rothenberger, G., Moser, J., Grätzel, M., Serpone, N., Sharma, D.K., (1985) J. Am. Chem. Soc., 107, p. 8054
  • Grätzel, M. In reference 6, p 159; Matthews, R.W., McEvoy, S.R., (1992) J. Photochem. Photobiol. A.: Chem., 66, p. 355
  • Janzen, E.G., Haire, D.L., (1990) Advances in Free Radical Chemistry, p. 253. , Tanner, D. D., Ed.; JAI Press: Greenwich, CT
  • Jaeger, C.D., Bard, A.J., (1979) J. Phys. Chem., 83, p. 3146
  • Harbour, J.H., Chew, V.S.F., Bolton, J.R., (1974) Can. J. Chem., 52, p. 3549
  • Kochany, J., Bolton, J.R., (1991) J. Phys. Chem., 95, p. 5117
  • Carmichael, A.J., Makino, K., Riesz, P., (1994) Radiat. Res., 100, p. 222
  • Harbour, J.R., Hair, M.L., (1978) J. Phys. Chem., 82, p. 1397
  • Calvert, J.G., Pitts, J.N., (1966) Photochemistry, p. 201. , Wiley: New York
  • Volman, D.H., Chen, J.C., (1959) J. Am. Chem. Soc., 81, p. 4141
  • Mendiara, S., Ghibaudi, E., Perissinotti, L.J., Colussi, A.J., (1992) J. Phys. Chem., 96, p. 8089
  • Churio, M.S., Brusa, M.A., Perissinotti, L.J., Ghibaudi, E., Coronel, M.E.J., Colussi, A.J., (1995) Chem. Phys. Lett., 232, p. 237
  • Defoin, A., Defoin-Straatmann, R., Hildenbrand, K., Bittersmann, E., Kreft, D., Kuhn, H.J., (1986) J. Photochem., 33, p. 237
  • Kuhn, H.J., Görner, H., (1988) J. Phys. Chem., 92, p. 6208
  • Kuhn, H.J., Defoin, A., (1986) EPA Newslett., 26, p. 23
  • Coronel, M.E.J., Colussi, A.J., (1994) J. Chem. Soc., Perkin Trans. 2, p. 985
  • Lepore, G.P., Langford, C.H., Víchová, J., Vlcek Jr., A., (1993) J. Photochem. Photobiol A: Chem., 75, p. 67
  • Abdullah, M., Low, G.K.-C., Matthews, R.W., (1990) J. Phys. Chem., 94, p. 6820
  • (1988) Spin Labeling: A Third Compendium, , Berliner, L. J., Ed.; Plenum: New York
  • Dalton, H., Wilkins, P.C., Deiahton, N., Podmore, I.D., Symons, M.C.R., (1992) Faraday Discuss., 93, p. 163
  • Ross, A.B., NDRL/NIST Solution Kinetics Database, Version 2.0, , Standard Reference Data, National Institute of Standards and Technology, Gaithersburg, MD 20899
  • note; Hoffman, A.J., Carraway, E.R., Hoffmann, M.R., (1994) Environ. Sci. Technol., 28, p. 776
  • Lepore, G.P., Pant, B.C., Langford, C.H., (1993) Can. J. Chem., 71, p. 2051
  • Bahnemann, D.W., Möning, J., Chapman, R., (1987) J. Phys. Chem., 91, p. 3782
  • Hong, A.P., Bahnemann, D.W., Hoffmann, M.R., (1987) J. Phys. Chem., 91, p. 2109
  • Kormann, C., Bahnemann, D.W., Hoffmann, M.R., (1988) J. Phys. Chem., 92, p. 5196
  • Anpo, M., Shima, T., Kodama, S., Kubokawa, Y., (1987) J. Phys. Chem., 91, p. 4305
  • Noda, H., Oikawa, K., Ohya-Nishiguchi, H., Kamada, H., (1994) Bull. Chem. Soc. Jpn., 67, p. 2031
  • Atkins, P.W., (1990) Physical Chemistry, 4th Ed., pp. 687-691. , W. H. Freeman: New York
  • Nargiello, M.; Herz, T. In reference 5, p 801; Steinfeld, J.I., Francisco, J.S., Hase, W.L., (1989) Chemical Kinetics and Dynamics, p. 161. , Prentice-Hall: New York
  • Kesselman, J. M.; Kumar, A.; Lewis, N. S. In reference 5, p 19; Wahl, A., Ulmann, M., Carroy, A., Jermann, B., Dolata, M., Kedziersawski, P., Chatelain, C., Augustynski, J., (1995) J. Electroanal. Chem., 396, p. 41
  • Wang, C.-M., Heller, A., Gerischer, H., (1992) J. Am. Chem. Soc., 114, p. 5230
  • Boxall, C., (1994) Chem. Soc. Rev., p. 137
  • Grela, M.A., Colussi, A.J., accepted for publication; Kopelman, R., (1988) Science, 241, p. 1620
  • O'Neil, M., Marohn, J., McLendon, G., (1990) J. Phys. Chem., 94, p. 4356
  • Nosaka, Y., Ohta, N., Miyama, H., (1990) J. Phys. Chem., 94, p. 3752
  • Brezová, V., Stasko, A., (1994) J. Catal., 147, p. 152
  • Brezová, V., Stasko, A., Biskupic, S., Blazková, A., Havlínová, B., (1994) J. Phys. Chem., 98, p. 8977
  • Sun, L., Bolton, J.R., (1996) J. Phys. Chem., 100, p. 4127
  • Sun, L., Hoy, A.R., Bolton, J.R., (1996) Adv. Oxidat. Technol., 1, p. 44
  • Sun, L., (1994), 186. , Doctoral Dissertation, Department of Chemistry, University of Western Ontario; Grela, M.A., Coronel, M.E.J., Colussi, A.J., to be submitted

Citas:

---------- APA ----------
Grela, M.A., Coronel, M.E.J. & Colussi, A.J. (1996) . Quantitative spin-trapping studies of weakly illuminated titanium dioxide sols. Implications for the mechanism of photocatalysis. Journal of Physical Chemistry, 100(42), 16940-16946.
http://dx.doi.org/10.1021/jp953562r
---------- CHICAGO ----------
Grela, M.A., Coronel, M.E.J., Colussi, A.J. "Quantitative spin-trapping studies of weakly illuminated titanium dioxide sols. Implications for the mechanism of photocatalysis" . Journal of Physical Chemistry 100, no. 42 (1996) : 16940-16946.
http://dx.doi.org/10.1021/jp953562r
---------- MLA ----------
Grela, M.A., Coronel, M.E.J., Colussi, A.J. "Quantitative spin-trapping studies of weakly illuminated titanium dioxide sols. Implications for the mechanism of photocatalysis" . Journal of Physical Chemistry, vol. 100, no. 42, 1996, pp. 16940-16946.
http://dx.doi.org/10.1021/jp953562r
---------- VANCOUVER ----------
Grela, M.A., Coronel, M.E.J., Colussi, A.J. Quantitative spin-trapping studies of weakly illuminated titanium dioxide sols. Implications for the mechanism of photocatalysis. 1996;100(42):16940-16946.
http://dx.doi.org/10.1021/jp953562r