Differences in the local structure and composition of anodic TiO2 nanotubes annealed in vacuum and air

Gavrilin, Ilya; Dronov, Alexey; Savchuk, Timofey; Dronova, Daria; Боргардт, Н. И.; Pavlikov, A. V.; Gavrilov, Sergey; Громов, Д. Г.

doi:10.1016/j.apsusc.2020.146120

Cited by 21 publications

(5 citation statements)

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“…[16]. The outer layer of the nanotube is almost stoichiometric anatase [16]. Also, the presence of carbon in IL nanotube multi-walled TiO 2 NTs after annealing in air has been described in [16,17].…”

Section: Introductionmentioning

confidence: 97%

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Anodic TiO₂ nanotube arrays for photocatalytic CO₂ conversion: comparative photocatalysis and EPR study

Savchuk¹,

Gavrilin²,

Константинова³

et al. 2021

Nanotechnology

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Titania (TiO2) is a widely used semiconductor for the photocatalytic decomposition of organic impurities in air, water and the conversion of CO2 into hydrocarbon fuel precursors. TiO2 in the form of nanotubes arrays is the most attractive for practical use because of the morphological advantages providing more favorable diffusion of photocatalytic reaction products and a low recombination rate of photogenerated electrons and holes. We have carried out a comparative study of the photocatalytic activity of gas-phase conversion of CO2 to hydrocarbon products and the defect properties of multi-walled and single-walled arrays of TiO2 nanotubes. Methanol and methane have been detected in the CO2 photoreduction process. The photocatalytic evolution rate of multi-walled TiO2 nanotubes is twice as fast for methane as for single-walled TiO2 nanotubes after four hours of irradiation and four times faster for methanol. The type and features of the structural defects have been investigated by EPR spectroscopy. For the first time, it has been shown that Ti3+/oxygen vacancy centers are mainly located inside the outer layer of nanotubes, while carbon dangling bonds have been observed directly on the surface of the inner layer. Carbon defects have been found to be the centers of adsorption and accumulation of photoinduced charge carriers. The results are entirely new; they clarify the role of different types of defects in the photocatalytic conversion of CO2 to hydrocarbon compounds and show good prospects for applying TiO2 nanotube arrays.

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Section: Introductionmentioning

confidence: 97%

“…After annealing, the inner layer of the nanotubes turns into a mesoporous structure with a mixture of anatase and rutile nanocrystals with an average size of ∼7 nm. [16]. The outer layer of the nanotube is almost stoichiometric anatase [16].…”

Section: Introductionmentioning

confidence: 99%

Anodic TiO₂ nanotube arrays for photocatalytic CO₂ conversion: comparative photocatalysis and EPR study

Savchuk¹,

Gavrilin²,

Константинова³

et al. 2021

Nanotechnology

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“…High-temperature annealing has proven to be an effective method for inducing the crystallization of amorphous TNTAs. 16,17 In the study of the annealing process, researchers have reached a consensus that the transformation of amorphous to anatase occurs around 300 °C, while the transformation from anatase to rutile occurs around 600 °C, causing the collapse of the nanotube array structure at this temperature. Interestingly, during the transformation from amorphous to anatase, the structure of the TNTAs does not undergo destructive damage.…”

Section: Introductionmentioning

confidence: 99%

Crystallization of amorphous anodized TiO₂ nanotube arrays

Wang,

Chen,

Xue

2024

RSC Adv.

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“…For many years, titanium dioxide (TiO 2 or titania) has maintained a leading position in the number of publications devoted to the development of new methods for the synthesis of this material both as a monophasic structure , and as part of nanostructures − or nanocomposites − with subsequent investigation of its physical and chemical properties. This continuing interest in TiO 2 is due to its high photoactivity, which manifests itself in the high rate of electron–hole pair generation and similar or higher rate of radical generation due to the capture of photoexcited charge carriers by water and oxygen molecules adsorbed on the titania surface. , This produces hydroxyl (OH • ) and superoxide anion (O 2 – ) radicals, starting an oxidation process and then degrading the pollutants.…”

Section: Introductionmentioning

confidence: 99%

Photoinduced Dynamics of Radicals in N- and Nb-Codoped Titania Nanocrystals with Enhanced Photocatalysis: Experiment and Modeling

Миннеханов

Kytina

Константинова

et al. 2022

Crystal Growth & Design

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Titanium dioxide (TiO2) nanocrystals are one of the most promising materials for modern photocatalysis applications, having unique properties such as a huge specific surface area and affordability of synthesis. However, the facile fabrication of TiO2-based photocatalysts active in regular daylight remains a major challenge. In this work, aiming to create such a nanocrystalline material by a very simple technology, we provide a detailed analysis of the paramagnetic centers (PCs) and their photoinduced reactions in N- and Nb-codoped TiO2 nanocrystals. The resulting powders show a surface area up to 170 m2/g and an intense visible-light photocatalysis of rhodamine 6G with reaction rate k = 0.087 min–1. Ti3+, N•, and O2 – PCs are observed and studied using electron paramagnetic resonance spectroscopy. We also present a new approach to the study of photoinduced processes in nanocrystalline photocatalystsa simple theoretical model of kinetics of these PCs, which well predicts their behavior and variations of their concentration under illumination. Our results indicate that the obtained Nb–N–TiO2 nanocrystals with a high concentration of PCs on the sample surface can be used in cutting-edge industries, paving the way for the most advanced photocatalytic systems operating in sunlight.

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Differences in the local structure and composition of anodic TiO2 nanotubes annealed in vacuum and air

Cited by 21 publications

References 67 publications

Anodic TiO₂ nanotube arrays for photocatalytic CO₂ conversion: comparative photocatalysis and EPR study

Anodic TiO₂ nanotube arrays for photocatalytic CO₂ conversion: comparative photocatalysis and EPR study

Crystallization of amorphous anodized TiO₂ nanotube arrays

Photoinduced Dynamics of Radicals in N- and Nb-Codoped Titania Nanocrystals with Enhanced Photocatalysis: Experiment and Modeling

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Differences in the local structure and composition of anodic TiO2 nanotubes annealed in vacuum and air

Cited by 21 publications

References 67 publications

Anodic TiO2 nanotube arrays for photocatalytic CO2 conversion: comparative photocatalysis and EPR study

Anodic TiO2 nanotube arrays for photocatalytic CO2 conversion: comparative photocatalysis and EPR study

Crystallization of amorphous anodized TiO2 nanotube arrays

Photoinduced Dynamics of Radicals in N- and Nb-Codoped Titania Nanocrystals with Enhanced Photocatalysis: Experiment and Modeling

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Product

Resources

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Anodic TiO₂ nanotube arrays for photocatalytic CO₂ conversion: comparative photocatalysis and EPR study

Anodic TiO₂ nanotube arrays for photocatalytic CO₂ conversion: comparative photocatalysis and EPR study

Crystallization of amorphous anodized TiO₂ nanotube arrays