Photocatalytic Characteristics of TiO<sub>2</sub>Thin Films Prepared by Dc Reactive Magnetron Sputtering with added H<sub>2</sub>O

Noguchi, Daisuke; Kawamata, Yoshio; Nagatomo, Takao

doi:10.1143/jjap.42.5255

Cited by 11 publications

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“…Beyond the optimum, as more oxygen vacancies are introduced into the films, photocatalytic activity is diminished because of a decrease in the thickness of the space-charge layer 38 resulting in the creation of recombination centers. 39 This differs from our observations of the reactivity of nonstoichiometric titania films and may be due to the fact that they only explored the metal mode and the oxidation mode, rather than the transition mode. 39 This differs from our observations of the reactivity of nonstoichiometric titania films and may be due to the fact that they only explored the metal mode and the oxidation mode, rather than the transition mode.…”

Section: B Photocatalytic Behaviorcontrasting

confidence: 85%

Effect of oxygen deficiency on the photoresponse and reactivity of mixed phase titania thin films

DeSario

Chen

Graham

et al. 2011

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Enhancement of optical absorption by modulation of the oxygen flow of TiO2 films deposited by reactive sputteringNonstoichiometric mixed phased titania nanocomposites ͑TiO 2−x ͒ were deposited by reactive direct current magnetron sputtering. The authors explored the role of nonstoichiometry ͑as defined by oxygen deficiency in synthesis͒ in mixed phase titania thin films and its effects on the photoresponse and photocatalytic performance for CO 2 reduction to methane under UV and visible light. Oxygen partial pressure was varied during film deposition, yielding different levels of oxygen deficiency in the films. Optimized nonstoichiometric films showed a strong redshift. The authors have identified an optimum set of synthesis conditions for TiO 2−x films that produce a relative maximum in photocatalytically produced methane under both UV and visible light. Redistribution subject to AVS license or copyright; see http://scitation.aip.org/termsconditions. Download to IP: 130.88.90.110 On: Mon, 22 Dec 2014 15:20:45 DeSario et al.: Effect of oxygen deficiency on the photoresponse and reactivity 031508-2 031508-2

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Section: B Photocatalytic Behaviorcontrasting

confidence: 85%

Effect of oxygen deficiency on the photoresponse and reactivity of mixed phase titania thin films

DeSario

Chen

Graham

et al. 2011

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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“…While on the other hand, the index for glass substrate was 1.6 [μmol l − 1 min − 1 ]. These results indicate that our films, deposited at such a high deposition rate, have similar MB decomposition performance to that of films obtained using reactive sputtering method [15][16][17].…”

Section: Photocatalytic Characteristicssupporting

confidence: 76%

High-rate deposition of photocatalytic TiO2 films by oxygen plasma assist reactive evaporation method

et al. 2008

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“…In all the films, broad peaks were observed at around 550 nm. Because peaks around 500-550 nm are associated with the degree of oxygen deficiencies, 9 it was verified that many degrees of deficiency, mainly oxygen deficiencies, exist in the forbidden band. The luminescence intensity mainly changes due to the degree of oxygen deficiencies …”

Section: Resultsmentioning

confidence: 99%

“…5 If we consider this matter from the aspect of process margins, however, many issues remain unsolved regarding the relationship between deposition conditions and the thin-film structure. Therefore, more in-depth structural analyses must be made if we are to improve control of the photocatalytic characteristics.…”

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confidence: 99%

Photocatalytic Characteristics and Structural Evaluation of TiO[sub 2] Thin Films Reactively DC Sputtered with H[sub 2]O

Noguchi

Kawamata²,

Nagatomo

2004

J. Electrochem. Soc.

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TiO 2 thin films containing Ti-OH bonds have been fabricated using dc reactive sputtering of Ti in a H 2 O ambient. The structures of these films and their photocatalytic characteristics were analyzed. The structures of the TiO 2 thin films were analyzed using Fourier transform infrared spectroscopic analysis, X-ray diffraction, scanning electron microscope inspection, nuclear magnetic resonance, and photoluminescence. To evaluate the photocatalytic characteristics of the TiO 2 films, we used a wet methylene blue method and pure-water contact angle measurement. We found the following: ͑i͒ The total quantity of OH groups decreases as the substrate temperature is increased. (ii) OH groups can be either densely or sparsely distributed in the TiO 2 film. (iii) The abundance ratios of the concentrated and sparse OH groups to the total quantity of OH groups change as the substrate temperature is increased. Measurements made with nuclear magnetic resonance and photoluminescence show that the sparse OH groups (͓OH͔ n ) are effective in removing oxygen deficiency and other deficiencies, while the localized, concentrated OH groups (͓OH͔ w ) are ineffective. We concluded that the distribution of OH groups in the TiO 2 thin film is an important factor that must be considered for improvement of photocatalytic characteristics.In 1972 Fujishima and Honda reported that water breaks down into hydrogen and oxygen due to the oxidation-reduction potential of electrons and holes generated when ultraviolet rays irradiate a TiO 2 electrode: this finding is known as the Honda-Fujishima effect. 1 TiO 2 photocatalysis has subsequently drawn a great deal of attention as a means of creating clean energy. TiO 2 photocatalysis is a photocatalytic decomposition process that takes place on the surface of a TiO 2 film. When the TiO 2 photocatalytic phenomenon occurs, electrons and holes generated by photoexcitation react with water and oxygen on the surface of the TiO 2 film, producing highly oxidative hydroxyl radicals ͑•OH͒ and superoxide anions (•O 2 Ϫ ).Various products are being developed based on TiO 2 photocatalysis: soil-resistant air cleaners for automobile interiors, for home and industrial use, soil-resistant tiles and tents that become soil resistant when exposed to sunlight, antimicrobial medical appliances such as antimicrobial catheters, products with a deodorizing function, and so forth. 2 It has been found that the surface of the TiO 2 film becomes ultrahydrophilic due to light excitation. 3 Products developed based on this ultrahydrophilic property of TiO 2 , such as the defogging of wing mirrors of automobiles, are now expanding their market. The ultrahydrophilic phenomenon can be explained as follows:Some of the electron-hole pairs generated during UV irradiation behave differently from others: they do not react with surface adsorbates, and their electrons reduce Ti 4ϩ and their holes oxidize O atoms in TiO 2 , thus producing O 2 gas and neutral O deficiencies (O v ), consequently giving rise to the ultrahydrophilic phenomeno...

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Photocatalytic Characteristics of TiO₂Thin Films Prepared by Dc Reactive Magnetron Sputtering with added H₂O

Cited by 11 publications

References 0 publications

Effect of oxygen deficiency on the photoresponse and reactivity of mixed phase titania thin films

Effect of oxygen deficiency on the photoresponse and reactivity of mixed phase titania thin films

High-rate deposition of photocatalytic TiO2 films by oxygen plasma assist reactive evaporation method

Photocatalytic Characteristics and Structural Evaluation of TiO[sub 2] Thin Films Reactively DC Sputtered with H[sub 2]O

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Photocatalytic Characteristics of TiO2Thin Films Prepared by Dc Reactive Magnetron Sputtering with added H2O

Cited by 11 publications

References 0 publications

Effect of oxygen deficiency on the photoresponse and reactivity of mixed phase titania thin films

Effect of oxygen deficiency on the photoresponse and reactivity of mixed phase titania thin films

High-rate deposition of photocatalytic TiO2 films by oxygen plasma assist reactive evaporation method

Photocatalytic Characteristics and Structural Evaluation of TiO[sub 2] Thin Films Reactively DC Sputtered with H[sub 2]O

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Photocatalytic Characteristics of TiO₂Thin Films Prepared by Dc Reactive Magnetron Sputtering with added H₂O