Photoinduced hydroxyl radical and photocatalytic activity of samarium-doped TiO2 nanocrystalline

Xiao, Qi; Si, Zhichun; Jiang, Zhang; Xiao, Chong; Tan, Xiaoke

doi:10.1016/j.jhazmat.2007.04.045

Cited by 334 publications

(179 citation statements)

References 33 publications

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“…Hydroxyl radicals OH· are known as major reactive species in photoreactions. [36][37][38] This mechanism shows why the concentration of Ni 2+ and H 2 match over time. It also explains of the absence of O 2 because most of the light induced holes are used to oxidize Ni to Ni 2+ via the OH· radical reaction.…”

Section: Structure-reactivity Relationsmentioning

confidence: 88%

Structural Evolution during Photocorrosion of Ni/NiO Core/Shell Cocatalyst on TiO₂

et al. 2015

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The Ni/NiO core/shell structure is one of the most efficient co-catalysts for solar water splitting when coupled with suitable semiconducting oxides. It has been shown that pretreated Ni/NiO core/shell structures are more active than pure Ni metal, pure NiO or mixed dispersion of Ni metal and NiO nanoparticles. However, Ni/NiO core/shell structures on TiO 2 are only able to generate H 2 but not O 2 in aqueous water. The nature of the hydrogen evolution reaction in these systems was investigated by correlating photochemical H 2 production with atomic resolution structure determined with aberration corrected electron microscopy. It was found that the core/shell structure plays an important role for H 2 generation but the system undergoes deactivation due to a loss of metallic Ni. During the H 2 evolution reaction, the metal core initially formed partial voids which grew and eventually all the Ni diffused out of the coreshell into solution leaving an inactive hollow NiO void structure. The H 2 evolution was generated by a photochemical reaction involving photocorrosion of Ni metal.3

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Section: Structure-reactivity Relationsmentioning

confidence: 88%

Structural Evolution during Photocorrosion of Ni/NiO Core/Shell Cocatalyst on TiO₂

et al. 2015

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“…The k values of samples without thermal treatment and those calcined at 300, 500, 600 and 700 °C were 0.01172, The photocatalytic activity of TiO 2 catalysts strongly depends on two factors: the adsorption behavior and the separation efficiency of electron-hole pairs [40][41][42][43]. Active oxygen species (such as hydroxyl radicals (OH), superoxide radicals (O 2 − ), and H 2 O 2 derived from the photogenerated electrons and holes) are considered to be the major active species responsible for the photocatalytic activity of TiO 2 [40][41][42].…”

Section: Photocatalytic Performance Evaluationmentioning

confidence: 96%

“…Active oxygen species (such as hydroxyl radicals (OH), superoxide radicals (O 2 − ), and H 2 O 2 derived from the photogenerated electrons and holes) are considered to be the major active species responsible for the photocatalytic activity of TiO 2 [40][41][42]. To further understand the photocatalytic mechanism of the as-synthesized brookite TiO 2 , hydroxyl radicals and hole trapping experiments were designed using 2-propanol as the radical scavenger and EDTA-2Na as the holes scavenger.…”

Section: Photocatalytic Performance Evaluationmentioning

confidence: 99%

Quasi-Spherical Brookite TiO2 Nanostructures Synthesized Using Solvothermal Method in the Presence of Oxalic Acid

Wang

Zou

Shang

et al. 2017

Trans. Tianjin Univ.

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Brookite TiO 2 , the latest TiO 2 photocatalyst, promises to be an interesting candidate for photocatalytic applications because of its unique physical and chemical properties. In this study, pure-phase brookite TiO 2 with a quasi-spherical nanostructure was successfully synthesized via a solvothermal method using tetrabutyl titanate (Ti(OC 4 H 9 ) 4 , TBOT) as the Ti source in the presence of oxalic acid. NaOH was used to regulate the pH of solution. The structure and morphology of the samples were then analyzed using multiple methods, such as X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) measurements and ultraviolet-visible diffuse spectroscopy (UV-Vis). Photocatalytic activities of the as-synthesized brookite TiO 2 were evaluated by degrading aqueous methylene blue solution under UV light irradiation. The effect of thermal treatment temperature on photocatalytic activity of the samples was also investigated. The produced brookite TiO 2 nanopowders calcined at 500 °C for 2 h showed the highest photocatalytic activity, and the corresponding degradation rate of methylene blue (10 mg/L) reached 96.7% after 90 min of illumination. In addition, the formation mechanism of pure-phase brookite TiO 2 was investigated. It was found that the formation of pure-phase brookite TiO 2 in this study was ascribed to the combined action of oxalic acid and sodium hydroxide.

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“…These produced radicals quantitatively convert coumarin (non-fluorescent species) to 7-hydroxycoumarin (fluorescent species) (Xiao et al 2008;Tryba et al 2007;Xiang et al 2011;Saif et al 2012;Ishibashi et al 2000). Fig.…”

Section: Characterization Of Tio 2 Nanoparticlesmentioning

confidence: 99%

Photocatalytic activity evaluation of TiO2 nanoparticles based on COD analyses for water treatment applications: a standardization attempt

EL-Mekkawi

Galal

Wahab

et al. 2016

Int. J. Environ. Sci. Technol.

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Evaluation of the photocatalytic activities of TiO 2 nanomaterials based on the chemical oxygen demand (COD) analyses under identical experimental conditions was not previously reported. In this work, COD has been selected as an adequate industrial water quality measure toward the establishment of a representative standard test method. The initial COD values of six organic pollutants representing dye, surfactants, phenols and alcohol were set at 30 ± 2 mg/L. Ten of different commercial and synthesized TiO 2 samples representing anatase, rutile and mixed phases were used and characterized. The data of photocatalytic processes were compared to that obtained using the commonly widespread Degussa-P25 TiO 2 (TD). The COD of all pollutants was completely removed by TD at UV exposure dose B9.36 mWh/cm 2 . Consequently, the maximum irradiation dose was set at this value in all experiments. The percentages of COD removal as well as the values of the accumulated UV doses required for complete removal of pollutants were measured using the different TiO 2 samples. TiO 2 samples show different performance abilities toward the various pollutants compared to TD. Based on the obtained data, TiO 2 photocatalysts were divided into two categories according to the hydroxyl radical formation rates. Comparison with previous studies reveals that the photocatalytic efficiency evaluation depends on the method of measurement. COD is recommended to be used as an adequate technique of analysis that meets the purpose of water treatment applications.

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Photoinduced hydroxyl radical and photocatalytic activity of samarium-doped TiO2 nanocrystalline

Cited by 334 publications

References 33 publications

Structural Evolution during Photocorrosion of Ni/NiO Core/Shell Cocatalyst on TiO₂

Structural Evolution during Photocorrosion of Ni/NiO Core/Shell Cocatalyst on TiO₂

Quasi-Spherical Brookite TiO2 Nanostructures Synthesized Using Solvothermal Method in the Presence of Oxalic Acid

Photocatalytic activity evaluation of TiO2 nanoparticles based on COD analyses for water treatment applications: a standardization attempt

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Photoinduced hydroxyl radical and photocatalytic activity of samarium-doped TiO2 nanocrystalline

Cited by 334 publications

References 33 publications

Structural Evolution during Photocorrosion of Ni/NiO Core/Shell Cocatalyst on TiO2

Structural Evolution during Photocorrosion of Ni/NiO Core/Shell Cocatalyst on TiO2

Quasi-Spherical Brookite TiO2 Nanostructures Synthesized Using Solvothermal Method in the Presence of Oxalic Acid

Photocatalytic activity evaluation of TiO2 nanoparticles based on COD analyses for water treatment applications: a standardization attempt

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Structural Evolution during Photocorrosion of Ni/NiO Core/Shell Cocatalyst on TiO₂

Structural Evolution during Photocorrosion of Ni/NiO Core/Shell Cocatalyst on TiO₂