Decrypting the growth of anodic TiO2 nanotube layers in eco-friendly fluoride-free nitrate-based electrolyte for enhanced photocatalytic degradation of organic pollutants

Thirunavukkarasu, Guru Karthikeyan; Hanif, Muhammad Bilal; Liapun, Viktoriia; Hensel, Karol; Kupčı́k, Jaroslav; Lörinčı́k, Jan; Elantyev, Ivan; Monfort, Olivier; Motola, Martin

doi:10.1016/j.materresbull.2023.112322

Cited by 11 publications

(3 citation statements)

References 63 publications

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“…As research progresses, the growth of porous anodic oxides has been achieved in electrolytes without fluoride ions. 20,21 This indicates that fluoride ions are not essential for the formation of porous anodic oxides, raising doubts about the traditional FAD theory, which attributes nanotube growth to fluoride ions. Additionally, some researchers have introduced boric acid into the conventional electrolyte and observed a significant reduction in nanotube length, 22 even when the concentration of NH 4 F remains unchanged.…”

Section: Introductionmentioning

confidence: 99%

“…While the FAD theory attributes the stable current in the third stage to the balance between the dissolution and formation rates of the dense oxide layer, studies have shown that the dissolution rate is significantly lower than the growth rate of the dense layer. , Moreover, FAD theory fails to explain the reason behind the inflection point observed in the current–time curve. As research progresses, the growth of porous anodic oxides has been achieved in electrolytes without fluoride ions. , This indicates that fluoride ions are not essential for the formation of porous anodic oxides, raising doubts about the traditional FAD theory, which attributes nanotube growth to fluoride ions. Additionally, some researchers have introduced boric acid into the conventional electrolyte and observed a significant reduction in nanotube length, even when the concentration of NH 4 F remains unchanged.…”

Section: Introductionmentioning

confidence: 99%

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Real Role of Fluoride Ions in the Growth of Anodic TiO₂ Nanotubes

Zhuang,

Li,

Qin

et al. 2024

J. Phys. Chem. C

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While porous anodic oxides have been extensively studied, there is limited research on the specific role of fluoride ions in the anodization. This study compares the morphology of titanium anodization products before and after the addition of ammonium pentaborate to the NH 4 F electrolyte. The current−time curve in anodization is analyzed to elucidate the real role of fluoride ions. The findings indicate that the real role of fluoride ions in the anodization is to form an anionic contaminated layer and cause the generation of electronic current, triggering the oxygen bubble mold effect and promoting nanotube growth. However, when pentaborate anions are introduced in the anionic contaminated layer, they hinder the production of electronic current, leading to a significant reduction in electronic current. Consequently, the growth rate of nanotubes decreases, resulting in the formation of bulb-shaped nanotube embryos. This study provides interesting evidence supporting the role of fluoride ions by combining the ionic and electronic current theory with the oxygen bubble mold effect. These pieces of evidence cast doubt on the simple chemical dissolution of fluoride ions in the traditional field-assisted dissolution theory. The experimental results significantly contribute to our understanding of the growth mechanism of porous anodic oxides.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Real Role of Fluoride Ions in the Growth of Anodic TiO₂ Nanotubes

Zhuang,

Li,

Qin

et al. 2024

J. Phys. Chem. C

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“…Simple and complex solid oxides are widely investigated in various fields of science and technology due to their diverse physical and chemical properties [1][2][3]. Complex solid oxides with high oxygen-ionic or protonic conductivity (i.e., electrolytes) are used in electrochemical devices for generating electricity (fuel cells) [4,5], producing gases (electrolyzers) [6,7], their purification (separating membranes) [8,9], and gas phase analysis (sensors) [10,11].…”

Section: Introductionmentioning

confidence: 99%

Highly Conductive Fe-Doped (La,Sr)(Ga,Mg)O3−δ Solid-State Membranes for Electrochemical Application

et al. 2023

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Membranes based on complex solid oxides with oxygen-ionic conductivity are widely used in high-temperature electrochemical devices such as fuel cells, electrolyzers, sensors, gas purifiers, etc. The performance of these devices depends on the oxygen-ionic conductivity value of the membrane. Highly conductive complex oxides with the overall composition of (La,Sr)(Ga,Mg)O3 have regained the attention of researchers in recent years due to the progress in the development of electrochemical devices with symmetrical electrodes. In this research, we studied how the introduction of iron cations into the gallium sublattice in (La,Sr)(Ga,Mg)O3 affects the fundamental properties of the oxides and the electrochemical performance of cells based on (La,Sr)(Ga,Fe,Mg)O3. It was found that the introduction of iron leads to an increase in the electrical conductivity and thermal expansion in an oxidizing atmosphere, while no such behavior was observed in a wet hydrogen atmosphere. The introduction of iron into a (La,Sr)(Ga,Mg)O3 electrolyte leads to an increase in the electrochemical activity of Sr2Fe1.5Mo0.5O6−δ electrodes in contact with the electrolyte. Fuel cell studies have shown that, in the case of a 550 µm-thick Fe-doped (La,Sr)(Ga,Mg)O3 supporting electrolyte (Fe content 10 mol.%) and symmetrical Sr2Fe1.5Mo0.5O6−δ electrodes, the cell exhibits a power density of more than 600 mW/cm2 at 800 °C.

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Review: influence of synthesis methods and performance of rare earth doped TiO2 photocatalysts in degrading dye effluents

Sari,

Gareso,

Tahir

2024

Int. J. Environ. Sci. Technol.

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Decrypting the growth of anodic TiO2 nanotube layers in eco-friendly fluoride-free nitrate-based electrolyte for enhanced photocatalytic degradation of organic pollutants

Cited by 11 publications

References 63 publications

Real Role of Fluoride Ions in the Growth of Anodic TiO₂ Nanotubes

Real Role of Fluoride Ions in the Growth of Anodic TiO₂ Nanotubes

Highly Conductive Fe-Doped (La,Sr)(Ga,Mg)O3−δ Solid-State Membranes for Electrochemical Application

Review: influence of synthesis methods and performance of rare earth doped TiO2 photocatalysts in degrading dye effluents

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Decrypting the growth of anodic TiO2 nanotube layers in eco-friendly fluoride-free nitrate-based electrolyte for enhanced photocatalytic degradation of organic pollutants

Cited by 11 publications

References 63 publications

Real Role of Fluoride Ions in the Growth of Anodic TiO2 Nanotubes

Real Role of Fluoride Ions in the Growth of Anodic TiO2 Nanotubes

Highly Conductive Fe-Doped (La,Sr)(Ga,Mg)O3−δ Solid-State Membranes for Electrochemical Application

Review: influence of synthesis methods and performance of rare earth doped TiO2 photocatalysts in degrading dye effluents

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Real Role of Fluoride Ions in the Growth of Anodic TiO₂ Nanotubes

Real Role of Fluoride Ions in the Growth of Anodic TiO₂ Nanotubes