Effect of fluoride and water content on the growth of TiO2 nanotubes synthesized via ethylene glycol with voltage changes during anodizing process

Quiroz, Heiddy P.; Quintero, Francisco; Arias, Pedro; Dussán, A.; Zea, Hugo

doi:10.1088/1742-6596/614/1/012001

Cited by 7 publications

(5 citation statements)

References 15 publications

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“…In this case, the current decay exponent is calculated to be À0. 47. The current decay exponent indicates the kinetics of the formation of a passivating layer on the surface.…”

Section: Resultsmentioning

confidence: 99%

“…Quiroz et al observed only 20% variation in the inner diameter of the nanotubes when the uoride concentration varied in EG-solution between 0.05 wt% to 0.25 wt%. 47 On the other hand, it can be argued that smaller nanotubes were formed on the already perturbed surface by the rst anodization based on the linear or weakly linear perturbation theory.…”

Section: Formation Mechanism Of the Honeycomb Morphologymentioning

confidence: 99%

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Self-ordering dual-layered honeycomb nanotubular titania: a study in formation mechanisms

Sitler

Raja

2016

RSC Adv.

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“…In this case, the current decay exponent is calculated to be À0. 47. The current decay exponent indicates the kinetics of the formation of a passivating layer on the surface.…”

Section: Resultsmentioning

confidence: 99%

Section: Formation Mechanism Of the Honeycomb Morphologymentioning

confidence: 99%

Self-ordering dual-layered honeycomb nanotubular titania: a study in formation mechanisms

Sitler

Raja

2016

RSC Adv.

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“…Consequently, such systems may work more effectively or allow for novel reaction pathways. In this regard, the length of the TiO 2 self-organized layers is usually adjusted mainly by applied voltage and also by selection of the anodization time and etching rate. , Geometry of the NTs can be also improved by modification of the electrolyte composition. Almost ideal hexagonally ordered arrays can be obtained in electrolyte composed of ethylene glycol (EG) containing fluoride species (HF, NH 4 F, NaF); however, other solvents, such as ionic liquids (ILs) and acetic acid, were also proposed.…”

Section: Introductionmentioning

confidence: 99%

Facile Formation of Self-Organized TiO₂ Nanotubes in Electrolyte Containing Ionic Liquid-Ethylammonium Nitrate and Their Remarkable Photocatalytic Properties

Pancielejko

Mazierski

Lisowski

et al. 2018

ACS Sustainable Chem. Eng.

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The oriented TiO 2 nanotube arrays (NTs) are identified as a stable, active, and recyclable photocatalytic surface. However, their photoactivity is strictly dependent on morphology (especially length), which could be controlled by anodic oxidation parameters, including electrolyte properties. To control the morphology a series of NTs were successfully synthesized by a novel approach where ionic liquid (IL), ethylammonium nitrate [EAN][NO 3 ], was used as an addition to an organic electrolyte. Using scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, diffuse reflectance UV−vis spectroscopy, and photoluminescence spectroscopy, we are able to show how electrolyte composition influences nanotubes' surface properties and photocatalytic activity. It was found that the change in the amount of [EAN][NO 3 ] in the electrolyte used for anodization in the range from 0.05 to 1.0 wt % affected dynamic viscosity, conductivity, and surface tension of the electrolyte and finally altered the morphology of the formed nanotubes resulting in a proportional increase of the outer diameter and tube length from 105 to 140 nm and from 6.0 to 8.1 μm, respectively. The highest photoactivity (achieving high reaction rate constant, equal to k = 0.0941 min −1 ) and wettability were found for the sample prepared in the electrolyte containing 0.05 wt % of [EAN][NO 3 ], revealing the improved ability to light photoabsorption and suppression of recombination rate. The increase of the contact angle from 9.3°to 13.1°with elongation of the tube diameter from 107 to 140 nm was also noted. It turned out that the IL_NTs' surface became more hydrophobic when stored in air ambience over 7 weeks after fabrication with approximately 20−52°.

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“…Experimental lattice constants reported for the three major phases of TiO 2 vary widely from one research group to another. ,− The variation may be due to the differences in the experimental conditions and the fitting methods adopted in measuring and refining the structural data. A similar attribute is notable of the data obtained using two DFT functionals and the three variants of the PAW potential, as well as when the Hubbard U (U = 3.0 eV) term was combined with GGA.…”

Section: Resultsmentioning

confidence: 99%

Polymorphs of Titanium Dioxide: An Assessment of the Variants of Projector Augmented Wave Potential of Titanium on Their Geometric and Dielectric Properties

et al. 2023

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Titanium dioxide (TiO2) is one of the important functional materials owing to its diverse applications in many fields of chemistry, physics, nanoscience, and technology. Hundreds of studies on its physicochemical properties, including its various phases, have been reported experimentally and theoretically, but the controversial nature of relative dielectric permittivity of TiO2 is yet to be understood. Toward this end, this study was undertaken to rationalize the effects of three commonly used projector augmented wave (PAW) potentials on the lattice geometries, phonon vibrations, and dielectric constants of rutile (R-)TiO2 and four of its other phases (anatase, brookite, pyrite, and fluorite). Density functional theory calculations within the PBE and PBEsol levels, as well as their reinforced versions PBE+U and PBEsol+U (U = 3.0 eV), were performed. It was found that PBEsol in combination with the standard PAW potential centered on Ti is adequate to reproduce the experimental lattice parameters, optical phonon modes, and the ionic and electronic contributions of the relative dielectric permittivity of R-TiO2 and four other phases. The origin of failure of the two soft potentials, namely, Ti_pv and Ti_sv, in predicting the correct nature of low-frequency optical phonon modes and ion-clamped dielectric constant of R-TiO2 is discussed. It is shown that the hybrid functionals (HSEsol and HSE06) slightly improve the accuracy of the above characteristics at the cost of a significant increase in computation time. Finally, we have highlighted the influence of external hydrostatic pressure on the R-TiO2 lattice, leading to the manifestation of ferroelectric modes that play a role in the determination of large and strongly pressure-dependent dielectric constant.

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Effect of fluoride and water content on the growth of TiO2 nanotubes synthesized via ethylene glycol with voltage changes during anodizing process

Cited by 7 publications

References 15 publications

Self-ordering dual-layered honeycomb nanotubular titania: a study in formation mechanisms

Self-ordering dual-layered honeycomb nanotubular titania: a study in formation mechanisms

Facile Formation of Self-Organized TiO₂ Nanotubes in Electrolyte Containing Ionic Liquid-Ethylammonium Nitrate and Their Remarkable Photocatalytic Properties

Polymorphs of Titanium Dioxide: An Assessment of the Variants of Projector Augmented Wave Potential of Titanium on Their Geometric and Dielectric Properties

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Effect of fluoride and water content on the growth of TiO2 nanotubes synthesized via ethylene glycol with voltage changes during anodizing process

Cited by 7 publications

References 15 publications

Self-ordering dual-layered honeycomb nanotubular titania: a study in formation mechanisms

Self-ordering dual-layered honeycomb nanotubular titania: a study in formation mechanisms

Facile Formation of Self-Organized TiO2 Nanotubes in Electrolyte Containing Ionic Liquid-Ethylammonium Nitrate and Their Remarkable Photocatalytic Properties

Polymorphs of Titanium Dioxide: An Assessment of the Variants of Projector Augmented Wave Potential of Titanium on Their Geometric and Dielectric Properties

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Product

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Facile Formation of Self-Organized TiO₂ Nanotubes in Electrolyte Containing Ionic Liquid-Ethylammonium Nitrate and Their Remarkable Photocatalytic Properties