Characterization of nanosized partly crystalline photocatalysts

Jensen, Henrik; Joensen, Karsten Dan; Jørgensen, Jens-Erik; Pedersen, Jan Skov; Søgaard, Erik Gydesen

doi:10.1007/s11051-004-1714-3

Cited by 105 publications

(92 citation statements)

References 15 publications

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“…that "theoretical intensity ratio" could be obtained and that P25 consisted of 73% anatase and 18% rutile [16], there was no interpretation on applicability of obtained calibration curves to fine titania particles such as P25.) There are at least two possible reasons for this fact.…”

Section: Crystalline Composition Analysesmentioning

confidence: 97%

What is Degussa (Evonik) P25? Crystalline composition analysis, reconstruction from isolated pure particles and photocatalytic activity test

Ohtani

Prieto-Mahaney

et al. 2010

Journal of Photochemistry and Photobiology A: Chemistry

831

541

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Anatase and rutile crystallites were isolated from Degussa (Evonik) P25 by selective dissolution with a hydrogen peroxide-ammonia mixture and diluted hydrofluoric acid, respectively, and used as standard samples for calibration curves of X-ray diffraction analyses.The results showed that P25 contains more than 70% anatase with a minor amount of rutile and a small amount of amorphous phase. The composition anatase/rutile/amorphous could be determined by analysis of P25 mixed with an internal standard, nickel(II) oxide.However, it was also found that the composition of P25 used in this study was inhomogeneous and changed depending on the position of sampling from the same package.Comparison of activities of original P25 and reconstructed P25 with those of isolated anatase and rutile particles suggested a less probable synergetic effect of the co-presence of anatase and rutile.

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Section: Crystalline Composition Analysesmentioning

confidence: 97%

What is Degussa (Evonik) P25? Crystalline composition analysis, reconstruction from isolated pure particles and photocatalytic activity test

Ohtani

Prieto-Mahaney

et al. 2010

Journal of Photochemistry and Photobiology A: Chemistry

831

541

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“…Crystallinity is an important photocatalyst property, but partly amorphous commercial catalysts are quite active in the photodegradation of pollutants [50]. Charge recombination, particularly surface recombination, can be sensibly high in poorly crystallized materials [49] due to a large number of defects.…”

Section: Epr Spin-trappingmentioning

confidence: 99%

Preparation and Photoactivity of Nanocrystalline TiO2 Powders Obtained by Thermohydrolysis of TiOSO4

et al. 2013

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Nanocrystalline TiO 2 photocatalysts were synthesized in mild conditions by thermohydrolysis of TiOSO 4 in water at 100°C and post-calcination treatment at various temperatures. The TiO 2 powders were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, specific surface area determinations, scanning electron microscopy and electron paramagnetic resonance measurements. The photoactivity of the samples was tested employing the photodegradation of 4-nitrophenol in liquid-solid regimen and the photooxidation of gaseous 2-propanol. The best results were obtained with the powder calcined at 600°C for 10 h. Surprisingly, the not calcined sample was the most active for the abatement of NO x under irradiation.

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“…Conversion and selectivity values for the heterogeneous runs were determined without considering the amounts of piperonyl alcohol and piperonal adsorbed onto the catalyst surface. The relative percentages of anatase, rutile and amorphous phases were determined by following the procedure reported by Jensen et al [28]. Total organic carbon (TOC) analyses were carried out by using a 5000A Shimadzu TOC analyzer.…”

Section: Samples Characterizationmentioning

confidence: 99%

“…The crystallinity of all of the samples was evaluated following the procedure by Jensen et al [28]. XRD diffractograms were recorded for mixtures of TiO 2 and CaF 2 (50%, w/w) and the areas of the 100% peaks of anatase (1 0 1), rutile (1 1 0) and CaF 2 (2 2 0) were determined.…”

Section: Samples Characterizationmentioning

confidence: 99%

Photocatalytic green synthesis of piperonal in aqueous TiO2 suspension

Bellardita

Loddo

Palmisano

et al. 2014

Applied Catalysis B: Environmental

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a b s t r a c tPiperonal (heliotropine or 3,4-methylenedioxybenzaldehyde) has been synthesized by oxidizing piperonyl alcohol in aqueous UV-irradiated TiO 2 suspensions. This compound was identified by GC-MS chromatography, 1 H NMR and melting point determination. The other products of the photoprocess were 1,3-bis(3,4-(methylenedioxy)benzyl) ether (found in traces) and CO 2 , derived from the parallel pathway of photo-mineralization. Commercial and home-prepared TiO 2 samples have been tested and the best selectivity (ca. 35%) was obtained by using the home-prepared ones. The reported green process allows to obtain an added value product (piperonal), upon partial oxidation of a cheap reagent.

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Characterization of nanosized partly crystalline photocatalysts

Cited by 105 publications

References 15 publications

What is Degussa (Evonik) P25? Crystalline composition analysis, reconstruction from isolated pure particles and photocatalytic activity test

What is Degussa (Evonik) P25? Crystalline composition analysis, reconstruction from isolated pure particles and photocatalytic activity test

Preparation and Photoactivity of Nanocrystalline TiO2 Powders Obtained by Thermohydrolysis of TiOSO4

Photocatalytic green synthesis of piperonal in aqueous TiO2 suspension

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