Resonant photoemission of anatase<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">TiO</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>(101) and (001) single crystals

Thomas, Andrew G.; Flavell, Wendy R.; Kumarasinghe, A.R.; Mallick, Arijit; Tsoutsou, D.; Smith, Graham C.; Stockbauer, Roger; Patel, Shelain; Grätzel, Michaël; Hengerer, R.

doi:10.1103/physrevb.67.035110

Cited by 135 publications

(91 citation statements)

References 35 publications

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“…[48], suggesting that, by itself, the synthesis method induces the 05 and 3.08 eV) are slightly lower than that of TiY0. The decreasing of the main band gap has been attributed to the band structure modification of titania by the introduction of dopants [48]. The secondary band gap is associated to the defect structure.…”

Section: Uv-vis Spectramentioning

confidence: 82%

Gold Nanoparticles on Yttrium Modified Titania: Support Properties and Catalytic Activity

et al. 2011

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A series of titanium oxide catalysts modified with yttrium has been prepared by sol-gel method and their structural properties have been studied. The incorporation of yttrium in the titania lattice favors the formation of oxygen vacancies while at low Y loadings the anatase structure is preserved. The catalytic activity of these solids for CO oxidation is found to be significantly dependent on their physical properties. In particular the amount of dopant controls the number of surface oxygen vacancies created as well as the gold particle size, which directly affects the catalytic activity. Also, a linear relationship between the catalytic activity and the band gap values, which depend on the Y loading, is observed. Density functional theory based calculations show that Y atoms are incorporated at the TiO 2 surface at substitutional positions only, while the preferred oxygen vacancies arise by removing the bridge surface oxygen atoms. These O-vacancies are the preferential adsorption sites for Au atoms and nanoparticles, acting as nucleation centers that favor the dispersion of the catalyst active phase over the support surface. In agreement with experiment, Y doping is found to decrease the band gap of the support due to a destabilization of the valence band of the oxide.

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Section: Uv-vis Spectramentioning

confidence: 82%

Gold Nanoparticles on Yttrium Modified Titania: Support Properties and Catalytic Activity

et al. 2011

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“…On the contrary, the anatase {001} facet is known to reconstruct under UHV conditions [9], which is usually an indication of low stability and high reactivity of the clean surface. In both {101} and {001} anatase oxygen vacancies are thought to lie beneath the surface [10,11]. Furthermore, minority {001} facets, having a high density of surface undercoordinated Ti atoms, exhibit higher reactivity for the dissociative adsorption of reactant molecules, such as water, methanol and formic acid, compared to the {101} facets [12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Specific Facets-Dominated Anatase TiO2: Fluorine-Mediated Synthesis and Photoactivity

2013

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Semiconductors crystal facet engineering has become an important strategy for properly tuning and optimizing both the physicochemical properties and the reactivity of photocatalysts. In this review, a concise survey of recent results obtained in the field of specific surface-oriented anatase TiO 2 crystals preparation is presented. The attention is mainly focused on the fluorine-mediated hydrothermal and/or solvothermal processes employed for the synthesis and the assembly of anatase micro/nanostructures with dominant {001} facets. Their peculiar photocatalytic properties and potential applications are also presented, with a particular focus on photocatalysis-based environmental clean up and solar energy conversion applications. Finally, the most promising results obtained in the engineering of TiO 2 anatase crystal facets obtained by employing alternative, possibly more environmentally friendly methods are critically compared.

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“…32-45͒ and have been reinvestigated more recently. [46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65] From the photoemission data on rutile 42,44,47,50,53,63 the electronic band gap, corresponding to the difference between the valence-band maximum ͑VBM͒ and the conduction-band minimum ͑CBM͒, has reported values of 3.3Ϯ 0.5 eV ͑Ref. 53͒ ͓ultraviolet photoemission spectroscopy ͑UPS͒ and inverse photoemission spectroscopy ͑IPES͔͒, 3.6Ϯ 0.2 eV ͑Ref.…”

Section: Introductionmentioning

confidence: 99%

Self-energy and excitonic effects in the electronic and optical properties ofTiO2crystalline phases

et al. 2010

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We present a unified ab initio study of electronic and optical properties of TiO 2 rutile and anatase phases with a combination of density-functional theory and many-body perturbation-theory techniques. The consistent treatment of exchange and correlation, with the inclusion of many-body one-particle and two-particles effects in self-energy and electron-hole interaction, produces a high-quality description of electronic and optical properties, giving, for some quantities, the first available estimation for this compound. In particular, we give a quantitative estimate of the electronic and direct optical gaps, clarifying their role with respect to previous measurements obtained by various experimental techniques. We obtain a description for both electronic gap and optical spectra that is consistent with experiments by analyzing the role of different contributions to the experimental optical gap and relating them to the level of theory used in our calculations. We also show the spatial properties of excitons in the two crystalline phases, highlighting the localization character of different optical transitions. This paper aims at understanding and firmly establishing electro-optical bulk properties, yet to be clarified, of this material of fundamental and technological interest for green energy applications.

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Resonant photoemission of anataseTiO2(101) and (001) single crystals

Cited by 135 publications

References 35 publications

Gold Nanoparticles on Yttrium Modified Titania: Support Properties and Catalytic Activity

Gold Nanoparticles on Yttrium Modified Titania: Support Properties and Catalytic Activity

Specific Facets-Dominated Anatase TiO2: Fluorine-Mediated Synthesis and Photoactivity

Self-energy and excitonic effects in the electronic and optical properties ofTiO2crystalline phases

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