Quantitative analysis of superoxide ion and hydrogen peroxide produced from molecular oxygen on photoirradiated TiO2 particles

Goto, Hajime; Hanada, Yasushi; Ohno, Teruhisa; Matsumura, Michio

doi:10.1016/j.jcat.2004.04.001

Cited by 295 publications

(114 citation statements)

References 34 publications

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“…The activated radicals play a role in degrading pollutants [45]. It is generally suggested that the rate-limiting steps of the photocatalytic reaction of semiconductors are electron–hole recombination and electron transfer from the semiconductor surface to the adsorbed oxygen molecules [45–48]. In our case, the pyrochlore phase can trap electrons from the conduction band of the semiconductor to reduce the electron–hole recombination, and to improve the charge separation efficiency.…”

Section: Resultsmentioning

confidence: 95%

Tm-doped TiO₂ and Tm₂Ti₂O₇ pyrochlore nanoparticles: enhancing the photocatalytic activity of rutile with a pyrochlore phase

Santos¹,

Navas²,

Aguilar³

et al. 2015

Beilstein J. Nanotechnol.

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SummaryTm-doped TiO2 nanoparticles were synthesized using a water-controlled hydrolysis reaction. Analysis was performed in order to determine the influence of the dopant concentration and annealing temperature on the phase, crystallinity, and electronic and optical properties of the resulting material. Various characterization techniques were utilized such as X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and UV–vis spectroscopy. For the samples annealed at 773 and 973 K, anatase phase TiO2 was obtained, predominantly internally doped with Tm3+. ICP–AES showed that a doping concentration of up to 5.8 atom % was obtained without reducing the crystallinity of the samples. The presence of Tm3+ was confirmed by X-ray photoelectron spectroscopy and UV–vis spectroscopy: the incorporation of Tm3+ was confirmed by the generation of new absorption bands that could be assigned to Tm3+ transitions. Furthermore, when the samples were annealed at 1173 K, a pyrochlore phase (Tm2Ti2O7) mixed with TiO2 was obtained with a predominant rutile phase. The photodegradation of methylene blue showed that this pyrochlore phase enhanced the photocatalytic activity of the rutile phase.

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Section: Resultsmentioning

confidence: 95%

Tm-doped TiO₂ and Tm₂Ti₂O₇ pyrochlore nanoparticles: enhancing the photocatalytic activity of rutile with a pyrochlore phase

Santos¹,

Navas²,

Aguilar³

et al. 2015

Beilstein J. Nanotechnol.

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“…However, given that charge transfer to O 2 readily facilitates its dissociation into O adatoms on the R TiO 2 (110) surface it is not unreasonable to expect that this species will be present on other TiO 2 surfaces. There have been numerous observations of this species being formed as a result of electron attachment arising from bandto-band excitation of TiO 2 [387,503,509,548,550,559,730,744,760,835,836,[838][839][840][854][855][856][857][858][859]]. An example of this (mentioned above) is O 2 photoadsorption where UV irradiation of TiO 2 generates adsorption sites for O 2 [387,556,778,787,789,860].…”

Section: Electron Scavengers: Omentioning

confidence: 99%

A surface science perspective on TiO2 photocatalysis

Henderson

2011

Surface Science Reports

1,872

1,634

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a b s t r a c tThe field of surface science provides a unique approach to understanding bulk, surface and interfacial phenomena occurring during TiO 2 photocatalysis. This review highlights, from a surface science perspective, recent literature that provides molecular-level insights into photon-initiated events occurring at TiO 2 surfaces. Seven key scientific issues are identified in the organization of this review. These are: (1) photon absorption, (2) charge transport and trapping, (3) electron transfer dynamics, (4) the adsorbed state, (5) mechanisms, (6) poisons and promoters, and (7) phase and form. This review ends with a brief examination of several chemical processes (such as water splitting) in which TiO 2 photocatalysis has made significant contributions in the literature.

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“…Then, the photo-excited electrons relax from the conduction band (CB) to the defect level to react with O 2 (electron acceptors) to form the O 2 − superoxide anion radicals; accordingly, the holes in the valence band react with water to form OH − hydroxyl radicals. Generally, the photo-catalytic property is mainly related to the amount of O 2 − [189]. However, because of the charge recombination process, the electrons that were necessary for the formation of O 2 − will get lost.…”

Section: Degradation Of Methylene Blue (Mb)mentioning

confidence: 99%

The Applications of Morphology Controlled ZnO in Catalysis

et al. 2016

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Zinc oxide (ZnO), with the unique chemical and physical properties of high chemical stability, broad radiation absorption range, high electrochemical coupling coefficient, and high photo-stability, is an attractive multifunctional material which has promoted great interest in many fields. What is more, its properties can be tuned by controllable synthesized morphologies. Therefore, after the success of the abundant morphology controllable synthesis, both the morphology-dependent ZnO properties and their related applications have been extensively investigated. This review concentrates on the properties of morphology-dependent ZnO and their applications in catalysis, mainly involved reactions on green energy and environmental issues, such as CO 2 hydrogenation to fuels, methanol steam reforming to generate H 2 , bio-diesel production, pollutant photo-degradation, etc. The impressive catalytic properties of ZnO are associated with morphology tuned specific microstructures, defects or abilities of electron transportation, etc. The main morphology-dependent promotion mechanisms are discussed and summarized.

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Quantitative analysis of superoxide ion and hydrogen peroxide produced from molecular oxygen on photoirradiated TiO2 particles

Cited by 295 publications

References 34 publications

Tm-doped TiO₂ and Tm₂Ti₂O₇ pyrochlore nanoparticles: enhancing the photocatalytic activity of rutile with a pyrochlore phase

Tm-doped TiO₂ and Tm₂Ti₂O₇ pyrochlore nanoparticles: enhancing the photocatalytic activity of rutile with a pyrochlore phase

A surface science perspective on TiO2 photocatalysis

The Applications of Morphology Controlled ZnO in Catalysis

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Quantitative analysis of superoxide ion and hydrogen peroxide produced from molecular oxygen on photoirradiated TiO2 particles

Cited by 295 publications

References 34 publications

Tm-doped TiO2 and Tm2Ti2O7 pyrochlore nanoparticles: enhancing the photocatalytic activity of rutile with a pyrochlore phase

Tm-doped TiO2 and Tm2Ti2O7 pyrochlore nanoparticles: enhancing the photocatalytic activity of rutile with a pyrochlore phase

A surface science perspective on TiO2 photocatalysis

The Applications of Morphology Controlled ZnO in Catalysis

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Product

Resources

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Tm-doped TiO₂ and Tm₂Ti₂O₇ pyrochlore nanoparticles: enhancing the photocatalytic activity of rutile with a pyrochlore phase

Tm-doped TiO₂ and Tm₂Ti₂O₇ pyrochlore nanoparticles: enhancing the photocatalytic activity of rutile with a pyrochlore phase