Effects of Silica-Coating on the Photoinduced Hole Formation and Decomposition Activity of Titanium Dioxide Photocatalysts Under UV Irradiation

Oguma, Junichi; Kakuma, Yusuke; Nishikawa, Masami; Nosaka, Yoshio

doi:10.1007/s10562-012-0914-1

Cited by 11 publications

(4 citation statements)

References 12 publications

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“…shows ESR spectra of anatase and rutile TiO 2 powders measured at 77K as the effect of UV light irradiation, which have been reported previousely. 28,29 For anatase, signals similar to the photoinduced-trapped holes appeared before photo irradiation, and the trapped electron disappeared due to the recombination with the trapped holes after the photoirradiation, indicating the presence of relatively-stable trapped holes. On the other hand, for rutile powder, the signal of the trapped holes was relatively small and the signal of the trapped electrons appeared.…”

Section: Generation Of Active Oxygensmentioning

confidence: 98%

Difference in TiO₂ photocatalytic mechanism between rutile and anatase studied by the detection of active oxygen and surface species in water

Kakuma

Nosaka

2015

Phys. Chem. Chem. Phys.

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160

125

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Various kinds of TiO2 photocatalysts have been practically applied in various fields. Knowing the exact surface properties is a prerequisite to develop further and efficient applications. However, the cause of the essential difference in the activities of the two polymorphs of TiO2, rutile and anatase, has not been clearly elucidated yet. We tried to clarify the cause in terms of active oxygen species (˙OH, ˙O2(-), and H2O2) photogenerated on the surfaces, which are considered practically involved in the photocatalytic reactions. It was revealed that for anatase the rate of ˙OH generation was high, but it decreased in the presence of H2O2. On the other hand, for rutile, ˙OH generation was very low but it increased in the presence of H2O2. The formation rate of ˙O2(-) for rutile was higher than that for anatase, suggesting that the photoinduced reduction process should not be accountable for the higher photocatalytic activity of anatase. Since the Ti-Ti distance on a rutile surface is smaller than that for anatase, rutile is capable of forming a surface structure such as Ti-OO-Ti, leading to readily form O2. The mechanism of fast coupling of two photoinduced conduction band holes to form Ti-OO-Ti was proposed, which is accountable for the lower reactivity of rutile. This mechanism was verified by the analysis of surface species with ATR-IR spectroscopy.

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Section: Generation Of Active Oxygensmentioning

confidence: 98%

Difference in TiO₂ photocatalytic mechanism between rutile and anatase studied by the detection of active oxygen and surface species in water

Kakuma

Nosaka

2015

Phys. Chem. Chem. Phys.

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160

125

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“…The Si in the silica framework was replaced by several heteroelements (Al and Ti) to design the surface properties and impart catalytic functions [ 81 – 83 ]. The photocatalytic properties of the heteroelement-doped silicas have been investigated.…”

Section: Synthesis Of Oxide-based Well-defined Particlesmentioning

confidence: 99%

Oxide-based inorganic/organic and nanoporous spherical particles: synthesis and functional properties

Shiba

Tagaya

Tilley

et al. 2013

Science and Technology of Advanced Materials

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This paper reviews the recent progress in the preparation of oxide-based and heteroatom-doped particles. Surfactant-templated oxide particles, e.g. silica and titania, are possible candidates for various potential applications such as adsorbents, photocatalysts, and optoelectronic and biological materials. We highlight nanoporous oxides of one element, such as silicon or titanium, and those containing multiple elements, which exhibit properties that are not achieved with individual components. Although the multicomponent nanoporous oxides possess a number of attractive functions, the origin of their properties is hard to determine due to compositional/structural complexity. Particles with a well-defined size and shape are keys for a quantitative and detailed discussion on the unique complex properties of the particles. From this viewpoint, we review the synthesis techniques of the oxide particles, which are functionalized with organic molecules or doped with heteroatoms, the physicochemical properties of the particles and the possibilities for their photofunctional applications as complex systems.

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“…Recently, the impact of coating extent of inorganic layers on the photocatalytic activity of TiO 2 nanoparticles has attracted great attention of researchers. When TiO 2 nanoparticles were coated by discontinuous silica layers, the resultant silica layer-coated TiO 2 nanoparticles had higher photocatalytic activities than the naked TiO 2 nanoparticles in the degradation of methyl blue and methyl orange under UV light irradiation. , Silica-doped TiO 2 particles also had higher photocatalytic activities than the naked TiO 2 particles in the gas-phase photocatalytic decomposition of toluene and acetaldehyde under UV light irradiation . Therefore, coating continuous and compact inorganic layers on pigmentary rutile TiO 2 particles is crucial in the suppression of photocatalytic activity.…”

Section: Introductionmentioning

confidence: 99%

“…18,19 Silica-doped TiO 2 particles also had higher photocatalytic activities than the naked TiO 2 particles in the gas-phase photocatalytic decomposition of toluene and acetaldehyde under UV light irradiation. 20 Therefore, coating continuous and compact inorganic layers on pigmentary rutile TiO 2 particles is crucial in the suppression of photocatalytic activity.…”

Section: Introductionmentioning

confidence: 99%

Preparation of TiO₂@ZrO₂@AlOOH@Polymethyl Acrylic Acid Nanocomposites and the Impact of Layer Structure on Color Scheme, Photocatalytic Activity, and Dispersion Stability

Shen

Cao

Wang

et al. 2020

Ind. Eng. Chem. Res.

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Triple zirconia/boehmite/polymethyl acrylic acid layer-coated pigmentary rutile TiO 2 nanocomposites were prepared by successive hydrolysis of zirconium sulfate and sodium meta-aluminate and in situ polymerization of methyl acrylic acid in aqueous solutions. Uniform, compact, and islandlike hydrous zirconia layers could be controllably coated on rutile TiO 2 particles by adjusting the hydrolysis pH value. At a 1 wt % alumina loading, boehmite nanoparticles were deposited on the zirconia-coating layer to form an islandlike boehmite-coating layer, whereas at a 2 wt % alumina loading, in addition to the islandlike boehmite coating layer, a flocculent boehmite layer was deposited. The zirconia and boehmite layers anchored at their substrates through Zr− O−Ti and Al−O−Zr bonding, respectively. The zirconia-coating layer obviously improved the whiteness and brightness of the pigmentary rutile TiO 2 powder. The binary zirconia/boehmite layers completely suppressed the photocatalytic activity of the rutile TiO 2 powder under UV light irradiation. The boehmite layers with a large amount of OH groups caused the aggregation of TiO 2 @ZrO 2 @AlOOH nanocomposites. Anchoring polymethyl acrylic acid molecules at the TiO 2 @ZrO 2 @AlOOH nanocomposite improved its dispersion stability in water. The as-prepared TiO 2 @ZrO 2 @AlOOH@MAA nanocomposite (where MAA is polymethyl acrylic acid) can be used as a white pigment in water-based-coating materials.

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Effects of Silica-Coating on the Photoinduced Hole Formation and Decomposition Activity of Titanium Dioxide Photocatalysts Under UV Irradiation

Cited by 11 publications

References 12 publications

Difference in TiO₂ photocatalytic mechanism between rutile and anatase studied by the detection of active oxygen and surface species in water

Difference in TiO₂ photocatalytic mechanism between rutile and anatase studied by the detection of active oxygen and surface species in water

Oxide-based inorganic/organic and nanoporous spherical particles: synthesis and functional properties

Preparation of TiO₂@ZrO₂@AlOOH@Polymethyl Acrylic Acid Nanocomposites and the Impact of Layer Structure on Color Scheme, Photocatalytic Activity, and Dispersion Stability

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Effects of Silica-Coating on the Photoinduced Hole Formation and Decomposition Activity of Titanium Dioxide Photocatalysts Under UV Irradiation

Cited by 11 publications

References 12 publications

Difference in TiO2 photocatalytic mechanism between rutile and anatase studied by the detection of active oxygen and surface species in water

Difference in TiO2 photocatalytic mechanism between rutile and anatase studied by the detection of active oxygen and surface species in water

Oxide-based inorganic/organic and nanoporous spherical particles: synthesis and functional properties

Preparation of TiO2@ZrO2@AlOOH@Polymethyl Acrylic Acid Nanocomposites and the Impact of Layer Structure on Color Scheme, Photocatalytic Activity, and Dispersion Stability

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Product

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Difference in TiO₂ photocatalytic mechanism between rutile and anatase studied by the detection of active oxygen and surface species in water

Difference in TiO₂ photocatalytic mechanism between rutile and anatase studied by the detection of active oxygen and surface species in water

Preparation of TiO₂@ZrO₂@AlOOH@Polymethyl Acrylic Acid Nanocomposites and the Impact of Layer Structure on Color Scheme, Photocatalytic Activity, and Dispersion Stability