Black Hydroxylated Titanium Dioxide Prepared via Ultrasonication with Enhanced Photocatalytic Activity

Fan, Chenyao; Chen, Chao; Wang, Jia; Fu, Xinxin; Ren, Zhimin; Qian, Guodong; Wang, Zhiyu

doi:10.1038/srep11712

Cited by 151 publications

(101 citation statements)

References 48 publications

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“…[ 104 ] However, in fact, the lattice disorder of anatase would be triggered mainly from the O sublattice, considering Adv. [ Figure 26 d. [ 94 ] Compared to the model A, model B resulted in the appearance of new states which extended from the valence band to more than 1.20 eV above the VBM, plus a small number of mid-gap states centered at about 1.80 eV above the VBM, as shown in Figure 26 e. [ 94,123 ] However, there are some different perspectives about disordered structure in black TiO 2 . 2016, 6, 1600452 www.MaterialsViews.com www.advenergymat.de that much more energy was required to deform the Ti sublattice than the O sublattice by the same amount, as shown in Figure 26 a and c. [ 104 ] So the experimentally observed bandgap reduction of hydrogenated black TiO 2 was mainly from the large blueshift of VBM.…”

Section: Electronic Structure Of Black Titaniamentioning

confidence: 97%

“…[ 94 ] The blackness of ultrasonic treated TiO 2 would be deeper with the extension of ultrasonic time. [ 94 ] The blackness of ultrasonic treated TiO 2 would be deeper with the extension of ultrasonic time.…”

Section: Other Approachesmentioning

confidence: 99%

“…[ 104 ] In this process, the Ti 3 O unit fi rst transformed into a V-shaped Ti 2 OH (Figure 24 c) by breaking one Ti-O bond, and then completely turned to be surface -OH and Ti-H after the second Ti-O bond broke, as shown in Figure 24 d. [ 104 ] As hydrogenation goes deeper below the anatase surface, the lattice will become more open, making it easier for reconstruction to occur. [ 94 ] Copyright 2015, Nature Publication Group. [ 104 ] That to some degree accounts for the surface disorder structure of hydrogenated black TiO 2 nanoparticles.…”

Section: Crystal Structure and Structure Evolution Of Black Titaniamentioning

confidence: 99%

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Progress in Black Titania: A New Material for Advanced Photocatalysis

Liu

Zhu

Wang

et al. 2016

Advanced Energy Materials

268

190

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excited charges should separate from each other and migrate to the surface to perform photocatalytic reactions, before they are annihilated in the recombination process. [ 3,17,18 ] Nevertheless, TiO 2 has a wide bandgap of 3.0−3.2 eV for the three common natural polymorphs -anatase, rutile and brookite. [ 8 ] That limits the optical absorption of TiO 2 in the ultraviolet (UV) region of the solar spectrum, resulting in insuffi cient utilization of solar energy (less than 5%). Another hurdle for TiO 2 material in the photo-chemical applications is its low quantum effi ciency that results from its high recombination of photo-generated electron-hole pairs. [ 16,18 ] Therefore, improving the optical absorption properties and reducing electron-hole recombination of TiO 2 are expected to be signifi cant for superior photoactivity.Various strategies have been adopted to tune TiO 2 's optical and electronic properties to improve its visible-light photoactivity. For example, metal ions (Co, Ni, Mn, Fe, Cr, …) or non-metal ions (N, S, C, I, …) are doped in the titania matrix to induce mid-gap states or to narrow the bandgap of TiO 2 , aiming to enhance its visible-light response. [ 3,17 ] Doping with open-shell metals is claimed to be benefi cial for red-shifting TiO 2 photochemistry into the visible, while closed shell cation dopants have no photochemical benefi t. Some d -block transition metal doping often generates deeply localized d -states in the forbidden bandgap of TiO 2 and results in recombination centers for carriers. [ 3,19 ] For the incorporation of non-metal ions, heavy doping is always diffi cult due to the large differences in chemistry between the alien ions and O 2− in titania, thus the visible light absorption is not signifi cantly enhanced. [ 20 ] Dye-sensitized or noble metal nanodots decorated TiO 2 nanostructures have been largely designed to enhanced its optical properties and to improve the charge separation effi ciency. [ 6,9,15,17,21 ] Additionally, charge separation in TiO 2 is believed to be effi ciently improved by forming heterojunctions with other semiconductors, such as metal oxides and chalcogenides. [ 6,22 ] In 2011, a hydrogenated black titania with a narrowed bandgap of ≈1.5 eV was reported to boost the full spectrum sunlight absorption and the photocatalytic activity. [ 23 ] This discovery has triggered world-wide scientifi c interests in black TiO 2 nanomaterials. [ 8 ] Black TiO 2 is featured by selfstructural modifi cations, involving self-doped Ti 3+ /oxygen vacancy, or incorporation of H-doping. [ 5,8 ] Owing to these modifi cations, their crystal and electronic structures as well as the surface property are signifi cantly changed, and the most marked effect is the color changing. The intrinsic TiO 2The photocatalytic activity of TiO 2 has aroused a broad range of research effort since 1972. Although TiO 2 has a very high effi ciency in utilizing ultraviolet light, its overall solar activity is very limited due to its wide bandgap (≈3.0−3.2 eV). This is a bottleneck for TiO 2 to...

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Section: Electronic Structure Of Black Titaniamentioning

confidence: 97%

Section: Other Approachesmentioning

confidence: 99%

Section: Crystal Structure and Structure Evolution Of Black Titaniamentioning

confidence: 99%

See 1 more Smart Citation

Progress in Black Titania: A New Material for Advanced Photocatalysis

Liu

Zhu

Wang

et al. 2016

Advanced Energy Materials

268

190

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“…The presence of ions such as hydroxyl, phosphate on the surface of nanomaterials increase photocatatlytic efficiency. Hydroxyl ions can adsorb on holes resulting in hydroxyl radical, while phosphate ions adsorb on holes, preventing the recombination1819.…”

mentioning

confidence: 99%

A New Synergetic Nanocomposite for Dye Degradation in Dark and Light

Prasanna

Vijayaraghavan

2016

Sci Rep

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Environmental hazard caused due to the release of dyes in effluents is a concern in many countries. Among the various methods to combat this problem, Advanced Oxidation Process, in which semiconductor photocatalysts are used, is considered the most effective one. These materials release Reactive Oxygen Species (ROS) such as hydroxyl radical and superoxide in suspension that degrade the dyes into non-toxic minerals. However, this process requires visible or UV light for activation. Hence, there is a need to develop materials that release ROS, both in the absence and in the presence of light, so that the efficiency of dye removal is enhanced. Towards this objective, we have designed and synthesized a new nanocomposite ZnO2/polypyrrole which releases ROS even in the dark. The ROS released in the dark and in light were estimated by standard methods. It is to be noted that ZnO2 degrades the dye only under UV light but not in dark or in the presence of visible light. We propose the mechanism of dye degradation in dark and light. The synergically coupled nanocomposite of ZnO2/ppy is the first example that degrades dyes in the dark, through advanced oxidation process without employing additional reagents.

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“…Moreover, hydrogenation procedures need a high annealing temperature (over 400°C) or high-pressure (e.g., 20 bar) and H 2 is flammable and explosive [16,17,[23][24][25][26]. The first attempt to prepare amorphous hydroxylated TiO 2 with various degrees of blackness was based on the ultrasonic irradiation of high power intensity with enhanced photocatalytic activity of acid fuchsin degradation [27] ( Table 1, Entry 1). A key feature of this system is that power density of employed ultrasonic irradiation was as high as 15 W mL -1 , and a low ultrasonic power density could not make such changes in colour.…”

Section: Sonochemical Synthesis Of Tio 2 Photocatalystmentioning

confidence: 99%

Synthesis of Photoactive Materials by Sonication: Application in Photocatalysis and Solar Cells

Colmenares

Kuna

Lisowski

2016

Topics in Current Chemistry Collections

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In recent years, a good number of methods have become available for the preparation of an important group of photoactive materials for applications in photocatalysis and solar cells. Nevertheless, the benefits derived from preparing those materials through unconventional approaches are very attractive from the green chemistry point of view. This critical review work is focused on sonication as one of these promising new synthetic procedures that allow control over size, morphology, nanostructure and tuning of catalytic properties. Ultrasound-based procedures offer a facile, versatile synthetic tool for the preparation of light-activated materials often inaccessible through conventional methods.

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Black Hydroxylated Titanium Dioxide Prepared via Ultrasonication with Enhanced Photocatalytic Activity

Cited by 151 publications

References 48 publications

Progress in Black Titania: A New Material for Advanced Photocatalysis

Progress in Black Titania: A New Material for Advanced Photocatalysis

A New Synergetic Nanocomposite for Dye Degradation in Dark and Light

Synthesis of Photoactive Materials by Sonication: Application in Photocatalysis and Solar Cells

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