Black TiO2 Nanomaterials: A Review of Recent Advances

Ullattil, Sanjay Gopal; Narendranath, Soumya B.; Pillai, Suresh C.; Periyat, Pradeepan

doi:10.1016/j.cej.2018.01.069

Cited by 308 publications

(161 citation statements)

References 219 publications

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“…However, surface defects are not stable enough as it can be spontaneously oxidized in air and water. So far, mainstream strategies to synthesize black/gray TiO 2−x are relied on the reduction of pristine stoichiometric TiO 2 [20][21][22][23][24], such as annealing under high pressures of H 2 or NH 3 , high-energy particle bombardment (hydrogen plasma, laser plasma, or high-energy electrons), and chemical reduction with reducing agent in vacuum. Apparently, it is significant and desirable to develop a simple and feasible strategy for massive production of black/gray TiO 2−x with engineered surface defects and related abundant solar absorption.Hereafter, we conduct a one-pot synthesis of gray TiO 2−x with large solar harvesting and engineered surface defects using a liquid-plasma technology at room temperature and atmospheric pressure [25].…”

mentioning

confidence: 99%

Liquid-Plasma Hydrogenated Synthesis of Gray Titania with Engineered Surface Defects and Superior Photocatalytic Activity

Zhang

Feng

et al. 2020

Nanomaterials

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Defect engineering in photocatalysts recently exhibits promising performances in solar-energy-driven reactions. However, defect engineering techniques developed so far rely on complicated synthesis processes and harsh experimental conditions, which seriously hinder its practical applications. In this work, we demonstrated a facile mass-production approach to synthesize gray titania with engineered surface defects. This technique just requires a simple liquid-plasma treatment under low temperature and atmospheric pressure. The in situ generation of hydrogen atoms caused by liquid plasma is responsible for hydrogenation of TiO 2 . Electron paramagnetic resonance (EPR) measurements confirm the existence of surface oxygen vacancies and Ti 3+ species in gray TiO 2−x . Both kinds of defects concentrations are well controllable and increase with the output plasma power. UV-Vis diffused reflectance spectra show that the bandgap of gray TiO 2−x is 2.9 eV. Due to its extended visible-light absorption and engineered surface defects, gray TiO 2−x exhibits superior visible-light photoactivity. Rhodamine B was used to evaluate the visible-light photodegradation performance, which shows that the removal rate constant of gray TiO 2−x reaches 0.126 min −1 and is 6.5 times of P25 TiO 2 . The surface defects produced by liquid-plasma hydrogenation are proved stable in air and water and could be a candidate hydrogenation strategy for other photocatalysts.Nanomaterials 2020, 10, 342 2 of 13 light absorption, prompting superior performances in photodegradation and water splitting [13][14][15]. The enhanced solar light absorption of black TiO 2 is ascribed to additional intermediate electronic states (e.g., V o or Ti 3+ states) and disorder surface caused by hydrogenation [16][17][18]. More importantly, defect engineering, for instance defects concentration and distribution, also plays an important role in tuning photocatalytic activity of black TiO 2 . It was reported that the high defect ratio of surface to bulk can significantly enhance the photoactivity owing to preferential diffusion from bulk to surface of photoinduced charges [19,20]. However, surface defects are not stable enough as it can be spontaneously oxidized in air and water. So far, mainstream strategies to synthesize black/gray TiO 2−x are relied on the reduction of pristine stoichiometric TiO 2 [20][21][22][23][24], such as annealing under high pressures of H 2 or NH 3 , high-energy particle bombardment (hydrogen plasma, laser plasma, or high-energy electrons), and chemical reduction with reducing agent in vacuum. Apparently, it is significant and desirable to develop a simple and feasible strategy for massive production of black/gray TiO 2−x with engineered surface defects and related abundant solar absorption.Hereafter, we conduct a one-pot synthesis of gray TiO 2−x with large solar harvesting and engineered surface defects using a liquid-plasma technology at room temperature and atmospheric pressure [25]. There has recently been increasing interest in liquid-plasma...

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mentioning

confidence: 99%

Liquid-Plasma Hydrogenated Synthesis of Gray Titania with Engineered Surface Defects and Superior Photocatalytic Activity

Zhang

Feng

et al. 2020

Nanomaterials

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“…This could be rationalized by considering that generating oxygen vacancies in TiO 2 can form as hallow donor level below the conductionb and, conducive to the band gap narrowing and visible light responseo f TiO 2 . [16,18] Figure 5c presentst he X-ray photoelectron valenceband (VB) spectra of DTMCs, TMCs, TTMCs, and TNCs, which illustrate that the VB maximum of DTMCs displays as light downward shift compared with that of TMCs,T TMCs, and TNCs. This is probably due to the band-blendinge ffects upon oxygen vacancy generation.…”

Section: Resultsmentioning

confidence: 99%

“…In recent years, the generation of oxygen vacancies (Ov) or the Ti 3 + state in TiO 2 to produce oxygen-deficient TiO 2 mesostructures has been proven an effectivew ay to extend the light absorption of TiO 2 to the visible light region. [15][16][17][18][19] Different from traditional doping strategies, the generation of Ov or the Ti 3 + state is au nique doping methodt hat can maintain the characteristic nature of TiO 2 .M eanwhile, this kind of doping can also enhancet he inherente lectroconductivity of TiO 2 and thus facilitatec harge transportation,e nhancing the corresponding efficiency of photoelectric conversion. [15,17,20] Consequently,r emarkably improved photocatalytic activity could be realized through fabricating oxygen-deficient TiO 2 mesostructures.…”

Section: Introductionmentioning

confidence: 99%

Oxygen‐Deficient Dumbbell‐Shaped Anatase TiO_2−x Mesocrystals with Nearly 100 % Exposed {101} Facets: Synthesis, Growth Mechanism, and Photocatalytic Performance

Cao

et al. 2019

Chemistry A European J

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The development of hierarchical TiO 2 superstructures with new morphologies and intriguing photoelectric properties for utilizing solar energy is known to be an effective approach to alleviatet he seriousp roblems of environmental pollution. Herein, uniqueo xygen-deficient dumbbellshaped anatase TiO 2Àx mesocrystals (DTMCs) enclosed by nearly 100 %{ 101} facets were readily synthesized by mesoscale transformation in TiCl 3 /acetic acid (HAc) mixed solution, followed by calcinationunder vacuum. These mesocrystals exhibited much higherp hotoreactivity toward removing the model pollutantsm ethyl orangea nd Cr VI than truncated tetragonalb ipyramidal anatase nanocrystals (TNCs), anatase mesocrystals built from truncated tetragonal bipyramidal anatase nanocrystals (TTMCs), and anatase mesocrystals con-structed by anatase nanocrystals with nearly 100 %e xposed {101} facets (TMCs), revealing that both the oxidation and reductiona bilities of anatase TiO 2 were simultaneously enhanced upon fabricating an oxygen-deficient mesocrystalline architecture with about 100 %e xposed {101} facets. Further characterization illustrated that such an enhancement of photoreactivity was mainly due to the strengthened light absorption, boosted chargec arrier separation, and nearly 100 %e xposed {101} facets of the oxygen-deficientd umbbell-shaped anatase mesocrystals. This work will be useful for guiding the synthesis of oxygen-deficient ordered superstructures of metal oxides with desired morphologies and exposed facets for promising applications in environmental remediation.

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“…At present, numerous metal oxides such as ZnO, CdS, TiO 2 , Bi 2 O 3 , and Fe 2 O 3 , have been investigated for their photocatalytic activities. Besides them, nickle oxide (NiO) is also a promising photocatalyst because of its characteristics of low cost, innocuity, high hole mobility, and high photosensitivity .…”

Section: Introductionmentioning

confidence: 99%

Bimetallic Metal‐Organic Framework Derived ZnO/Ni_0.9Zn_0.1O Nanocomposites for Improved Photocatalytic Degradation of Organic Dyes

Zhong

Zhao

et al. 2020

ChemistrySelect

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An optimized structure is of considerable importance for nickle oxide (NiO)‐based materials to achieve high performance as catalyst for contaminant degradation due to the inherent large band gap. Herein, a series of hybrids of NiO nanoparticles doped with zinc oxide (ZnO) semiconductor were fabricated via a facile one‐step calcination of bimetallic metal‐organic frameworks with varied Ni2+/Zn2+ molar ratios (MOF‐NiZn). It is worth noting that partial positions of Ni in NiO lattice are replaced by Zn to form a Ni0.9Zn0.1O phase. Benefiting from the unique hybrid advantage, the rationally designed material could effectively lower the band gap of NiO, thus improving the photocatalytic performance. The optimized ZnO/Ni0.9Zn0.1O‐82 catalyst exhibits the highest degradation activity towards methylene blue (MB) with efficiency up to 97.4 % within 60 min. Additionally, the radicals trapping experiments reveal that the photo‐generated hydroxyl radical (.OH) is the predominant active species during the photodegradation of MB.

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Black TiO2 Nanomaterials: A Review of Recent Advances

Cited by 308 publications

References 219 publications

Liquid-Plasma Hydrogenated Synthesis of Gray Titania with Engineered Surface Defects and Superior Photocatalytic Activity

Liquid-Plasma Hydrogenated Synthesis of Gray Titania with Engineered Surface Defects and Superior Photocatalytic Activity

Oxygen‐Deficient Dumbbell‐Shaped Anatase TiO_2−x Mesocrystals with Nearly 100 % Exposed {101} Facets: Synthesis, Growth Mechanism, and Photocatalytic Performance

Bimetallic Metal‐Organic Framework Derived ZnO/Ni_0.9Zn_0.1O Nanocomposites for Improved Photocatalytic Degradation of Organic Dyes

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Black TiO2 Nanomaterials: A Review of Recent Advances

Cited by 308 publications

References 219 publications

Liquid-Plasma Hydrogenated Synthesis of Gray Titania with Engineered Surface Defects and Superior Photocatalytic Activity

Liquid-Plasma Hydrogenated Synthesis of Gray Titania with Engineered Surface Defects and Superior Photocatalytic Activity

Oxygen‐Deficient Dumbbell‐Shaped Anatase TiO2−x Mesocrystals with Nearly 100 % Exposed {101} Facets: Synthesis, Growth Mechanism, and Photocatalytic Performance

Bimetallic Metal‐Organic Framework Derived ZnO/Ni0.9Zn0.1O Nanocomposites for Improved Photocatalytic Degradation of Organic Dyes

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Oxygen‐Deficient Dumbbell‐Shaped Anatase TiO_2−x Mesocrystals with Nearly 100 % Exposed {101} Facets: Synthesis, Growth Mechanism, and Photocatalytic Performance

Bimetallic Metal‐Organic Framework Derived ZnO/Ni_0.9Zn_0.1O Nanocomposites for Improved Photocatalytic Degradation of Organic Dyes