Certified reference materials for quantification of vanadate species in anodic alumina Rf-GDOES depth profiles

Ifezue, D.

doi:10.1039/c3ja50061f

Cited by 2 publications

(2 citation statements)

References 9 publications

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“…4)), anodic alumina formation starts. Molybdate ions, as well as vanadates, 60 can also form the nonporous oxide on the surface of the aluminum and thus prevent its dissolution at the beginning of the process. It can explain the formation of the dense cracked layer sites on the film surface.…”

Section: Resultsmentioning

confidence: 99%

Aluminum Anodizing in an Aqueous Solution of Formic Acid with Ammonium Heptamolybdate Additive

Chernyakova

Jasulaitienė

Naujokaitis

et al. 2023

J. Electrochem. Soc.

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Morphology, composition, and fluorescence properties of anodic alumina/carbon composites formed in an aqueous solution of formic acid with ammonium heptamolybdate additive were studied concerning the amount and state of embedded carbon. According to scanning electron microscopy, the composites possess a hierarchical structure with multi-branched pores with a dense, cracked cover layer on the film surface. On the reverse side, hexagonal-shaped cells with an average diameter of about 180 nm were formed. Linear sweep voltammetry and current transient curves demonstrated that the anodizing process is non-steady. Thermogravimetry/differential thermal analysis showed that the average carbon content is ca. 5.5 mass.%. According to infrared spectroscopy, carbon embedded in the alumina is in the form of CO2, CO, carboxylate ions, and a-C:H. X-ray-induced Auger electron spectroscopy of the surface and reverse sides of the films proved that carbon is homogeneously distributed through the oxide layer. According to fluorescence studies, alumina/carbon composites have a wide blue fluorescence in the wavelength range of 350–700 nm with a maximum at around 455–460 nm. The fluorescence spectrum dynamics is non-exponential and can be described as a superposition of several decay components. These can be different carbon-containing compounds and functional groups, such as OH, C=O, and COOH.

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Section: Resultsmentioning

confidence: 99%

Aluminum Anodizing in an Aqueous Solution of Formic Acid with Ammonium Heptamolybdate Additive

Chernyakova

Jasulaitienė

Naujokaitis

et al. 2023

J. Electrochem. Soc.

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“…It is worth noting that, in acidic solutions, vanadic acid transforms to a meta state, which further tends to polymerize into di-, tetra-, and decavanadic acids depending on the pH value [ 20 ]. The current transience, i a ( t ), ( Figure 1 a) as well as anodic potential–time, E a ( t ), plots ( Figure 1 b) recorded for Al anodized in pure 0.2 mol·L −1 sodium vanadate solution verified the formation of a barrier-layer film [ 21 ]. The thickness of this layer ( δ b ) determined by ellipsometry was about 116–121 nm.…”

Section: Resultsmentioning

confidence: 99%

Designing Carbon-Enriched Alumina Films Possessing Visible Light Absorption

et al. 2022

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Aluminum anodization in an aqueous solution of formic acid and sodium vanadate leads to the formation of alumina/carbon composite films. This process was optimized by varying the concentrations of formic acid and sodium vanadate, the pH, and the processing time in constant-voltage (60–100 V) or constant-current mode. As estimated, in this electrolyte, the anodizing conditions played a critical role in forming thick, nanoporous anodic films with surprisingly high carbon content up to 17 at.%. The morphology and composition of these films were examined by scanning electron microscopy, ellipsometry, EDS mapping, and thermogravimetry coupled with mass spectrometry. For the analysis of incorporated carbon species, X-ray photoelectron and Auger spectroscopies were applied, indicating the presence of carbon in both the sp2 and the sp3 states. For these films, the Tauc plots derived from the experimental diffuse reflectance spectra revealed an unprecedentedly low bandgap (Eg) of 1.78 eV compared with the characteristic Eg values of alumina films formed in solutions of other carboxylic acids under conventional anodization conditions and visible-light absorption.

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Certified reference materials for quantification of vanadate species in anodic alumina Rf-GDOES depth profiles

Cited by 2 publications

References 9 publications

Aluminum Anodizing in an Aqueous Solution of Formic Acid with Ammonium Heptamolybdate Additive

Aluminum Anodizing in an Aqueous Solution of Formic Acid with Ammonium Heptamolybdate Additive

Designing Carbon-Enriched Alumina Films Possessing Visible Light Absorption

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