Comparison of photooxidation and photoreduction reactions on TiO2 nanoparticles

Egerton, Terry A.; Mattinson, John A.

doi:10.1016/j.jphotochem.2006.07.018

Cited by 23 publications

(27 citation statements)

References 16 publications

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“…Overall, the solid state n.m.r. results give confidence that the silica does not exist as a separate silica precipitate [26]. Analogous experiments on alumina coated TiO 2 are more difficult to interpret, because of the quadrupole moment of 27 Al [25].…”

Section: Rutilementioning

confidence: 86%

“…The strategy was repeated for the silica-on-rutile series 2S prepared from rutile #2 [26]. The results ( Figure 7A) again show that, above 1% silica, deposition of silica reduces the activity for propan-2-ol photocatalytic oxidation.…”

Section: Photocatalytic Oxidation Of Propan-2-olmentioning

confidence: 90%

“…To determine the effect of a hydrous oxide coating layer on photocatalytic reduction two reactions, the reduction of DPPH (1,1-diphenyl-2-picrylhydrazyl radical) and photogreying of TiO 2 were used [26,32].…”

Section: Photocatalytic Reduction Of Dpph and Photogreyingmentioning

confidence: 99%

“…The experiments were carried on a dispersions of TiO 2 (0.25 g dm M) in a 50:50 mix of mineral oil and caprylic acid triglyceride (MOTG; supplied by Uniqema) using a similar cell to that used for the propan-2-ol oxidation. The stable free radical, diphenyl picryl hydrazine, DPPH, is purple and has a broad absorption from 400 to 800 nm centred at 520 nm [26]. The DPPH readily captures an electron to form DPPH which then captures a proton from the solvent to form yellow DPPH 2 .…”

Section: Photocatalytic Reduction Of Dpph ·mentioning

confidence: 99%

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The Influence of Surface Alumina and Silica on the Photocatalytic Degradation of Organic Pollutants

Egerton

2013

Catalysts

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Practical photocatalysis for degradation of organic pollutants must take into account the influence of other chemicals. Significant Al deposition on titania can occur at naturally occurring concentrations of dissolved Al. This paper reviews the author's work on the influence of deliberately deposited hydrous oxides of aluminium on the behavior of a ~130 m 2 g −1 rutile TiO 2 , and then compares the behavior of deposited alumina with that of deposited silica. On rutile some adsorbed nitrogen is infrared-active. Alumina and silica deposited on the rutile reduce, and ultimately eliminate, this infrared-active species. They also reduce photocatalytic oxidation of both propan-2-ol and dichloroacetate ion and the photocatalytic reduction of diphenyl picryl hydrazine. The surface oxides suppress charge transfer and may also reduce reactant adsorption. Quantitative measurement of TiO 2 photogreying shows that the adsorbed inorganics also reduce photogreying, attributed to the capture of photogenerated conduction band electrons by Ti 4+ to form Ti 3+ . The influence of adsorbed phosphate on photocatalysis is briefly considered, since phosphate reduces photocatalytic disinfection. In the context of classical colloid studies, it is concluded that inorganic species in water can significantly reduce photoactivity from the levels that measured in pure water.

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Section: Rutilementioning

confidence: 86%

Section: Photocatalytic Oxidation Of Propan-2-olmentioning

confidence: 90%

Section: Photocatalytic Reduction Of Dpph and Photogreyingmentioning

confidence: 99%

Section: Photocatalytic Reduction Of Dpph ·mentioning

confidence: 99%

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The Influence of Surface Alumina and Silica on the Photocatalytic Degradation of Organic Pollutants

Egerton

2013

Catalysts

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“…Although many organic chemicals undergo photo-oxidation, photo-reduction reactions may occur depending on the redox properties of the chemical [7][8][9]. There has been much debate as to whether photoreactions occur on the surface of TiO2 or in the bulk solution.…”

Section: Introductionmentioning

confidence: 99%

Adsorption and Photocatalytic Degradation of Aqueous Solution of Polar Organic Pollutants

2009

Al-Azhar Bulletin of Science

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This study examines the adsorption and the photodegradation of isopropanol and its degradation intermediate, acetone, as a polar organic pollutant. Both isopropanol (100 mg/L) and formed acetone are shown to be effectively photodegraded in aqueous suspensions of 2g/L TiO2. It was found that dark adsorption isothermal of isopropanol on the surface of TiO 2 was unfavoured process, which suggesting that the photodegradation reaction occurred in the bulk solution (homogeneous) rather than on the surface (heterogeneous) of the photocatalyst. In addition, homogeneous reaction is further confirmed by the decrease of the degradation rate of isopropanol in presence of 1x10 -4 M tetranitromethane (TNM) which is effectively eliminating the formation of free OH• radicals in the bulk solution. Under the studied conditions, the parent isopropanol and its degradation product, acetone, were completely degraded from aqueous solution in about 2.5 -5.5 h.

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Screening tests for the evaluation of nanoparticle titania photocatalysts

Thompson

Goodall

Kellici

et al. 2009

J of Chemical Tech & Biotech

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BACKGROUND: Nano-sized titanium dioxide has potential as a photocatalyst, and doped variants may have different photocatalytic properties. Nano-titanias with a wide range of dopants and compositions can be prepared using continuous hydrothermal flow synthesis (CHFS), but when many samples are made, a large-scale screening test is required to investigate their properties. A range of doped nano-titanias were prepared using a CHFS route, and investigated as powders using a range of photocatalytic test methods. These tests included decolourization of methylene blue (in the presence of oxygen), partial oxidation of a simple alcohol (propan-2-ol) and the degradation of aqueous solutions of dichloroacetic acid. The practicality of the tests for large-scale screening was considered, and the test results were cross-correlated to see if any of them gave similar ranking for activity of the photocatalysts.

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Comparison of photooxidation and photoreduction reactions on TiO2 nanoparticles

Cited by 23 publications

References 16 publications

The Influence of Surface Alumina and Silica on the Photocatalytic Degradation of Organic Pollutants

The Influence of Surface Alumina and Silica on the Photocatalytic Degradation of Organic Pollutants

Adsorption and Photocatalytic Degradation of Aqueous Solution of Polar Organic Pollutants

Screening tests for the evaluation of nanoparticle titania photocatalysts

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