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Hainer A, Joshi N, Scaiano JC. Laser flash photolysis of titanium dioxide suspensions for the evaluation of solvent-mediated radical reactions. Phys Chem Chem Phys 2023; 25:2747-2751. [PMID: 36625327 DOI: 10.1039/d2cp05170b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The chemistry originating from the scavenging of the highly electrophilic hole in TiO2 can be readily monitored using laser flash photolysis techniques. Dilute suspensions are sufficiently transparent in the UV region that long lived signals from reactions of solvent radicals with 1,1-diphenylethylene can be readily monitored. Transient signals originating from hole, electron and trapped radicals are extremely long lived showing stretched exponentials (nanoseconds to milliseconds), adequately described by fractal models.
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Affiliation(s)
- Andrew Hainer
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie Curie, Ottawa, ON K1N 6N5, Canada.
| | - Neeraj Joshi
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie Curie, Ottawa, ON K1N 6N5, Canada.
| | - Juan C Scaiano
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie Curie, Ottawa, ON K1N 6N5, Canada.
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2
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Schneider J, Nikitin K, Dillert R, Bahnemann DW. Laser-flash-photolysis-spectroscopy: a nondestructive method? Faraday Discuss 2017; 197:505-516. [DOI: 10.1039/c6fd00193a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein, we report the effect of the laser illumination during the diffuse-reflectance laser-flash-photolysis measurements on the morphological and optical properties of TiO2 powders. A grey-blue coloration of the TiO2 nanoparticles has been observed after intense laser illumination. This is explained by the formation of nonreactive trapped electrons accompanied by the release of oxygen atoms from the TiO2 matrix as detected by means of UV-vis and EPR spectroscopy. Moreover, in the case of the pure anatase sample a phase transition of some TiO2 nanoparticles located in the inner region from anatase to rutile occurred. It is suggested that these structural changes in TiO2 are caused by an energy and charge transfer to the TiO2 lattice.
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Affiliation(s)
- Jenny Schneider
- Leibniz University Hannover
- Institute for Technical Chemistry
- 30167 Hannover
- Germany
| | - Konstantin Nikitin
- Leibniz University Hannover
- Institute for Technical Chemistry
- 30167 Hannover
- Germany
- Saint-Petersburg State University
| | - Ralf Dillert
- Leibniz University Hannover
- Institute for Technical Chemistry
- 30167 Hannover
- Germany
| | - Detlef W. Bahnemann
- Leibniz University Hannover
- Institute for Technical Chemistry
- 30167 Hannover
- Germany
- Saint-Petersburg State University
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3
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Kükrer Kaletas B, Kozhevnikov VN, Zimine M, Williams RM, König B, De Cola L. Sensitization of Nanocrystalline TiO2 Films with Carboxy-Functionalized Bis(indolyl)maleimide. European J Org Chem 2005. [DOI: 10.1002/ejoc.200500043] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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4
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Da Silva JP, Vieira Ferreira LF. Surface photochemistry of pesticides: an approach using diffuse reflectance and chromatography techniques. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2004; 38:2849-2856. [PMID: 15212259 DOI: 10.1021/es0348501] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The photochemistry of pesticides triadimenol and triadimefon was studied on cellulose and beta-cyclodextrin (beta-CD) in controlled and natural conditions, using diffuse reflectance techniques and chromatographic analysis. The photochemistry of triadimenol occurs from the chlorophenoxyl moiety, while the photodegradation of triadimefon also involves the carbonyl group. The formation of 4-chlorophenoxyl radical is one of the major reaction pathways for both pesticides and leads to 4-chlorophenol. Triadimenol also undergoes photooxidation and dechlorination, leading to triadimefon and dechlorinated triadimenol, respectively. The other main reaction process of triadimefon involves alpha-cleavage from the carbonyl group, leading to decarbonylated compounds. Triadimenol undergoes photodegradation at 254 nm but was found to be stable at 313 nm, while triadimefon degradates in both conditions. Both pesticides undergo photochemical decomposition under solar radiation, being the initial degradation of rate per unit area of triadimefon 1 order of magnitude higher than the observed for triadimenol in both supports. The degradation rates of the pesticides were somewhat lower in beta-CD than on cellulose. Photoproduct distribution of triadimenol and triadimefon is similar for the different irradiation conditions, indicating an intramolecular energy transfer from the chlorophenoxyl moiety to the carbonyl group in the latter pesticide.
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Affiliation(s)
- José P Da Silva
- Centro de Química-Física Molecular, Instituto Superior Técnico, 1049-001 Lisboa, Portugal.
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5
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Formation of dimer radical cation of 1,1-dianisylethylene through two-step hole transfer processes during TiO2 photocatalytic reactions. Tetrahedron Lett 2004. [DOI: 10.1016/j.tetlet.2004.03.072] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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6
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Tachikawa T, Tojo S, Fujitsuka M, Majima T. Influences of Adsorption on TiO2 Photocatalytic One-Electron Oxidation of Aromatic Sulfides Studied by Time-Resolved Diffuse Reflectance Spectroscopy. J Phys Chem B 2004. [DOI: 10.1021/jp037003t] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Takashi Tachikawa
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
| | - Sachiko Tojo
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
| | - Mamoru Fujitsuka
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
| | - Tetsuro Majima
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
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7
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Da Silva JP, Vieira Ferreira LF, Da Silva AM, Oliveira AS. Photochemistry of 4-chlorophenol on cellulose and silica. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2003; 37:4798-4803. [PMID: 14594394 DOI: 10.1021/es026448c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The photochemistry of 4-chlorophenol (4-CP) was studied on silica and cellulose, using time-resolved diffuse reflectance techniques and product degradation analysis. The results have shown that the photochemistry of 4-CP depends on the support, on the concentration, and also on the sample preparation method. Transient absorption and photoproduct results can be understood by assuming the formation of the carbene 4-oxocyclohexa-2,5-dienylidene in both supports. On cellulose, at concentrations lower than 10 micromol g(-1), the carbene leads to the unsubstituted phenoxyl radical, and phenol is the main degradation product. At higher concentrations a new transient resulting from phenoxyl radicals coupling was also observed, and dihydroxybiphenyls are also formed. The reaction of the carbene with ground-state 4-CP was also detected through the formation of 5-chloro-2,4'-dihydroxybiphenyl. 4-Chlorophenoxyl radical and degradations products resulting from its coupling were also detected. Oxygen has little effect on the photochemistry of 4-CP on cellulose. On silica the transient benzoquinone O-oxide was formed in the presence of oxygen. Benzoquinone and hydroquinone are the main degradation products. In well-dried samples the formation of hydroquinone is reduced. At higher concentrations the same products as detected on cellulose were observed. 4-CP undergoes slow photochemical decomposition under solar radiation in both supports. The same main degradation products were observed in these conditions.
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Affiliation(s)
- José P Da Silva
- Centro de Química-Física Molecular, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.
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Da Silva J, Vieira Ferreira L, Da Silva A, Oliveira A. A comparative study of the photophysics and photochemistry of 4-chlorophenol adsorbed on silicalite and β-cyclodextrin. J Photochem Photobiol A Chem 2002. [DOI: 10.1016/s1010-6030(02)00178-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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9
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Shirgaonkar IZ, Pandit AB. Sonophotochemical destruction of aqueous solution of 2,4,6-trichlorophenol. ULTRASONICS SONOCHEMISTRY 1998; 5:53-61. [PMID: 11270337 DOI: 10.1016/s1350-4177(98)00013-3] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The combination of ultrasound and photochemistry have been used to degrade an aqueous solution of 2,4,6-trichlorophenol. An ultrasonic probe of 22 kHz frequency and a UV tube of 15 W have been used. Anatase grade TiO2 was used as the semiconductor catalyst. The effect of parameters such as ultrasonic intensity, operating conditions, type of ultrasonic equipment, and mode of UV transmission have been studied. The sonophotochemical degradation has been found to be dependent on the intensity of sonication, temperature of the reaction, and the type of ultrasonic equipment used, but was independent of the mode of UV transmission. Enhancement in the degradation rate has been observed at a higher sonication intensity and temperature of the solution.
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Affiliation(s)
- I Z Shirgaonkar
- University Department of Chemical Technology, University of Mumbai (Bombay), Matunga, Mumbai, Bombay 400019, India
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10
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Colombo DP, Bowman RM. Does Interfacial Charge Transfer Compete with Charge Carrier Recombination? A Femtosecond Diffuse Reflectance Investigation of TiO2 Nanoparticles. ACTA ACUST UNITED AC 1996. [DOI: 10.1021/jp9610628] [Citation(s) in RCA: 176] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- D. Philip Colombo
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045
| | - Robert M. Bowman
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045
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11
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Acceleration of secondary dark reactions of intermediates derived from adsorbed dyes on irradiated TiO2 powders. J Photochem Photobiol A Chem 1996. [DOI: 10.1016/1010-6030(96)04342-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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12
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Lepore GP, Langford CH, Víchová J, Vlček A. Photochemistry and picosecond absorption spectra of aqueous suspensions of a polycrystalline titanium dioxide optically transparent in the visible spectrum. J Photochem Photobiol A Chem 1993. [DOI: 10.1016/1010-6030(93)80161-2] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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13
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Wilkinson F, McGarvey DJ, Worrall DR. The application of diffuse reflectance laser photolysis to study photochemistry at interfaces and in dyed fabrics. J CHEM SCI 1992. [DOI: 10.1007/bf02839120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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14
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Wilkinson F, Worrall DR. Diffuse reflectance laser photolysis studies of the mechanisms of light-induced reactions in heterogeneous systems. J CHEM SCI 1992. [DOI: 10.1007/bf02863373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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15
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Wilkinson F. Diffuse reflectance laser flash photolysis of adsorbed molecules. J CHEM SCI 1991. [DOI: 10.1007/bf02842087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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16
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Wilkinson F, Kelly GP, Michael C, Oelkrug D. A study of the photophysical properties of various triaryl-2-pyrazolines in solution and microcrystalline form. J Photochem Photobiol A Chem 1990. [DOI: 10.1016/1010-6030(90)80009-m] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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17
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Laser Flash Photolysis on Solid Surfaces. ACTA ACUST UNITED AC 1989. [DOI: 10.1016/s0167-2991(08)61180-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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18
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Photoelectrochemistry in particulate systems. Photosensitized charge injection into opaque TiO2 semiconductor powder as probed by time-resolved diffuse reflectance laser flash photolysis. Chem Phys Lett 1988. [DOI: 10.1016/0009-2614(88)80370-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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