Ultrasmall Metal Oxide Particles: Preparation, Photophysical Characterization, and Photocatalytic Properties

Israel Journal of Chemistry - Tập 33 Số 1 - Trang 115-136 - 1993
Detlef W. Bahnemann1
1Institut für Solarenergieforschung GmbH, Sokelantstrasse 5, D‐30165 Hannover 1, Germany

Tóm tắt

Abstract

This paper gives an overview of the author's activities in the research of extremely small metal oxide particles in recent years. In particular, the synthesis of transparent colloidal solutions of extremely small zinc oxide, titanium dioxide, hematite, and titanium/iron mixed oxide particles (2 nm < d 20 nm) in water, ethanol, and 2‐propanol is described. Quantum (Q)‐size effects are observed during particle growth and at me final stages of synthesis. A simple molecular orbital (MO) picture is presented for the qualitative interpretation of these effects, while quantitative calculations have been carried out using a quantum mechanical model developed by Brus. The photophysical properties of the particles have also been investigated extensively. Fluorescence spectra of the ZnO sols suggest that adsorbed electron relays are necessary to shuttle electrons from the conduction band to lower‐lying traps. Excess negative charge on the particles, resulting from either deprotonated surface hydroxyl groups or from photogenerated or externally injected charge carriers, causes a blue‐shift in the electronic absorption spectrum, which is explained by electrostatic and MO models. The zero point of charge (pHzpc) of the aqueous colloidal suspensions has been determined by several independent methods. While zinc oxide, titanium dioxide, and titanium/iron mixed oxide particles exhibit considerable photocatalytic activity (as illustrated for the reduction of molecular oxygen and the oxidation of various halogenated carboxyl acids), hematite particles are only found to oxidize S(IV) under bandgap illumination to a reasonable extent (ϕ < 0.3). A mechanism involving surface‐bound molecules and free radical intermediates is presented to explain these differences in reactivity.

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Tài liệu tham khảo

10.1021/ar00072a003

10.1021/j100259a006

10.1016/0360-3199(85)90025-4

10.1021/j100403a003

10.1063/1.445676

10.1063/1.447218

Ekimov A.I., 1981, JETP Lett., 34, 345

Ekimov A.I., 1984, JETP Lett., 40, 1136

10.1016/S0038-1098(85)80025-9

10.1063/1.445834

10.1063/1.447228

10.1063/1.448727

10.1063/1.449407

10.1021/j100406a018

10.1002/bbpc.19840880715

10.1002/bbpc.19840881010

10.1016/0009-2614(85)80287-6

10.1002/bbpc.19860900107

10.1016/0009-2614(85)80553-4

10.1021/ja00263a005

10.1016/0009-2614(85)87255-9

10.1016/0009-2614(86)85075-8

10.1016/0009-2614(86)80094-X

Tanaka T., 1983, Photogr. Sci., 31, 13, 10.1080/00223638.1983.11738194

Tanaka T., 1985, Imaging Sci., 29, 86

10.1016/0022-2313(84)90221-7

10.1021/j100249a004

10.1103/PhysRevB.33.5953

10.1007/BFb0018073

10.1021/cr00098a010

10.1146/annurev.pc.41.100190.002401

10.1021/j100155a009

10.1163/156856791X00093

10.1021/ar00005a002

10.1021/j100298a015

10.1021/j100329a027

10.1021/j100354a021

10.1021/es00172a009

10.1016/1010-6030(89)87099-6

10.1021/es00015a018

10.1007/978-94-011-3396-8_15

10.1016/0038-092X(90)90070-S

10.1002/bbpc.198800297

Fox M.A., 1986, Chim. Ind., 68, 59

10.1016/0010-8545(86)85009-3

10.1007/BF03051818

Serpone N., 1989, Photocatalysis: Fundamentals and Applications

Fox M.A., 1988, Photoinduced Electron Transfer Part A‐D

Pelizzetti E., 1986, Homogeneous and Heterogeneous Photocatalysis (NATO ASI series, Series C: Mathematical and Physical Sciences, 10.1007/978-94-009-4642-2

Schiavello M., 1988, Photocatalysis and Environment: Trends and Applications, 10.1007/978-94-009-3015-5

10.1007/BFb0018072

Pelizzetti E.;Barbeni M.;Pramauro E.;Erbs W.;Borgarello E.;Jamieson M.A.;Serpone N.Quimica Nova1985:288.

10.1021/j100678a001

10.1039/P29810000341

10.1021/ac60289a021

10.1021/es00151a015

10.1002/prac.18710030126

10.1016/0022-3697(80)90105-5

10.1016/0021-9797(67)90266-4

10.1016/0022-1902(66)80100-8

Weast R.C., 1985, CRC Handbook of Chemistry and Physics, D‐92

Schindler P., 1963, Gazz. Chim. Ital., 93, 168

10.1002/hlca.19640470409

10.1002/hlca.19650480528

10.1016/0009-2614(86)80410-9

Atkins P.W., 1978, Physical Chemistry, 485

Brus L.E., 1987, Nouv. J. Chim., 11, 123

10.1103/PhysRev.124.1719

10.1016/0031-8914(66)90082-6

10.1103/PhysRevB.18.5606

Agekyan V.T., 1980, Sov. Phys. Solid State, 22, 6

Landolt‐Börnstein, 1982, Zahlenwerte und Funktionen aus Naturwissenschaft und Technik

10.1021/j100298a014

Mott N.F., 1979, Electronic Processes in Non‐Crystalline Materials, 273

Bockelmann D.;Jirkovsky J.;Bahnemann D.Langmuir1992 in preparation.

Stumm W., 1981, Aquatic Chemistry:, 625

10.1021/cr60234a002

10.1007/BF02716019

10.1021/j150340a005

Nicoll F.H., 1948, J. Opt. Soc. Am., 38, 478

10.1007/BF01340694

10.1016/0038-1098(71)90623-5

10.1016/0022-2313(76)90120-4

10.1016/S0081-1947(08)60481-6

Riehl N., 1956, Ber. Bunsenges. Phys. Chem., 60, 149

10.1103/PhysRevLett.23.579

10.1016/0022-2313(79)90020-6

10.1002/pssa.2210650165

10.1016/0040-6090(83)90191-8

Many M., 1974, CRC Critical Reviews in Solid State Sciences, 515

10.1021/j100211a014

10.1039/f19858101999

10.1007/978-3-642-47547-4_3

10.1021/ja00375a006

10.1002/bbpc.19820860313

10.1021/ic00208a026

Henglein A., 1969, Einführung in die Strahlenchemie:, 168

10.1016/0304-5102(87)80047-0

10.1351/pac198052122649

10.1063/1.555739

10.1016/0021-9797(84)90206-6

10.1021/es00151a015

10.1021/es00136a002

10.1016/0043-1354(86)90020-5

10.1021/j150645a024

10.1149/1.2131532

10.1021/es00013a016

Hilgendorff M., 1991, Diplomarbeit:

Schindler P., 1987, In Aquatic Surface Chemistry, 83

10.1021/j100334a049

10.1021/j100308a035

10.1021/j150667a042

Thông tin
Thông tin xuất bản

Israel Journal of Chemistry

Tập 33 Số 1

115-136

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