XPS study of Li ion intercalation in V2O5 thin films prepared by thermal oxidation of vanadium metal

Światowska-Mrowiecka, Jolanta; Maurice, Vincent; Zanna, Sandrine; Klein, Lorena H.; Marcus, Philippe

doi:10.1016/j.electacta.2006.12.050

Cited by 128 publications

(116 citation statements)

References 40 publications

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“…Interestingly, the cyclic voltammograms show a significant difference in the redox potential of Vn as compared with that of Vb ( Supplementary Fig. 14c) 50,51 . These observations confirm that the quantum size confinement of Vn alters the redox potential and enhances the stability of the þ 5 oxidation state of vanadium during the entire catalytic cycle.…”

Section: Resultsmentioning

confidence: 99%

An antioxidant nanozyme that uncovers the cytoprotective potential of vanadia nanowires

et al. 2014

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Nanomaterials with enzyme-like properties has attracted significant interest, although limited information is available on their biological activities in cells. Here we show that V 2 O 5 nanowires (Vn) functionally mimic the antioxidant enzyme glutathione peroxidase by using cellular glutathione. Although bulk V 2 O 5 is known to be toxic to the cells, the property is altered when converted into a nanomaterial form. The Vn nanozymes readily internalize into mammalian cells of multiple origin (kidney, neuronal, prostate, cervical) and exhibit robust enzyme-like activity by scavenging the reactive oxygen species when challenged against intrinsic and extrinsic oxidative stress. The Vn nanozymes fully restore the redox balance without perturbing the cellular antioxidant defense, thus providing an important cytoprotection for biomolecules against harmful oxidative damage. Based on our findings, we envision that biocompatible Vn nanowires can provide future therapeutic potential to prevent ageing, cardiac disorders and several neurological conditions, including Parkinson's and Alzheimer's disease.

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Section: Resultsmentioning

confidence: 99%

An antioxidant nanozyme that uncovers the cytoprotective potential of vanadia nanowires

et al. 2014

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“…Transfer to the XPS analysis chamber was performed via a glove box (Jacomex) under Ar atmosphere with H 2 O and O 2 contents lower than 1 ppm, and directly connected to a VG ESCALAB 250 spectrometer, thus avoiding exposure of the sample to laboratory air. [12] Exposure of the thermal oxide film to Cl − -containing water was performed by immersing the sample in a 0.5 M NaCl(aq) solution prepared from ultra pure chemicals (Merck) and Millipore  water (resistivity >18 M cm, pH 5.8) at room temperature in cumulated steps. This required the transfer of the sample from the XPS spectrometer to the immersion cell and vice versa through air.…”

Section: Introductionmentioning

confidence: 99%

X‐ray photoelectron spectroscopy study of the interaction of ultra‐thin alumina films on NiAl alloys with NaCl solutions

Bennour

Maurice

Marcus

2010

Surface & Interface Analysis

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We report a XPS study of the reactivity in 0.5 M NaCl aqueous solution of NiAl(100) surfaces covered by ultra-thin aluminium oxide films grown by thermal oxidation of the alloy at 900• C. Detailed analysis of the film thickness, the oxide stoichiometry and the alloy composition below the oxide was performed to characterize the drastic modifications induced by chloride exposure. Chloride entry in the oxide was observed by AR-XPS that revealed the existence of two chemical states of chlorides, one associated to aluminium oxide, the other one to aluminium hydroxide. The film modifications were initiated in the inner part and characterized by the formation of chloride-containing hydroxide species. The growth of these species spread later to the entire film, accompanied by a marked thickening of the modified alumina layer by selective oxidation of the alloy. Longer immersion times (>20 h) led to the formation of mixed nickel-aluminium chloride-containing hydroxide species, indicating the loss of corrosion protection.

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“…Figure 5a presents a schematic cross section of the AA 2024-T3 sample coated with the TCP conversion layer with PACS post-treatment, where three locations for XPS analysis were prepared by ToF-SIMS depth sputtering using a Cs + ion beam (135 nA, 2 keV, 1000 × 1000 μm 2 ): (i) non-sputtered extreme surface, (ii) craters at a depth of 10 nm, (iii) another crater at a depth of 40 nm. The samples prepared in the ToF-SISM chamber were then transferred from the ToF-SIMS to the XPS analysis chamber in a sealed container under argon atmosphere, using the glove-boxes connected directly to the ToF-SIMS and the XPS spectrometers, 50 in order to avoid sample contamination or oxidation. Argon ion beam sputtering is known to lead to reduction of different compounds i.e.…”

Section: 33mentioning

confidence: 99%

Role of Post-Treatment in Improved Corrosion Behavior of Trivalent Chromium Protection (TCP) Coating Deposited on Aluminum Alloy 2024-T3

Ely

Światowska

Seyeux

et al. 2017

J. Electrochem. Soc.

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The effects of post-treatment applied on Trivalent Chromium Protection (TCP) coatings deposited on aluminum alloy 2024-T3 was studied by electrochemical and surface analytical techniques: X-ray Photoelectron Spectroscopy (XPS) and Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS). The aim of the post-treatment was to improve the corrosion resistance of the TCP coating. To understand the influence of the post-treatment, using a bath containing H 2 O 2 and a lanthanum salt as an inhibitor, our approach was to study the effect of these two components separately. It was found that the improved corrosion protection provided by the post-treated TCP was related to a synergetic effect of the two components. XPS and ToF-SIMS analyses showed that (i) the thickness of the TCP coating is not modified by the post-treatment, (ii) lanthanum is present on the surface and in the bulk of the TCP and (iii) is found in very small amount only on the extreme surface. The total concentration of Cr(VI) (oxide/hydroxide) was estimated to be below 0.1 wt% in the post-treated TCP layer. It was concluded that lanthanum plays a significant role in improving the coating density and homogeneity and has a beneficial effect on the TCP coating cracking as observed by Scanning Electron Aluminum alloys are used for aerospace applications for their low weight and good mechanical properties.1-3 To improve the corrosion properties of aluminum alloys and to provide good paint adhesion, the first layer of coating applied on the aluminum alloy surface used to be a chromate conversion coating (CCC).4-6 However, hexavalent chromium used in the CCC coatings is highly toxic, 4,7 its use is very much restricted in Europe 8 and the United States 9 and will be forbidden by 2024 by the European Community with respect to the Registration, Evaluation, Authorization and Restriction of Chemicals (REACh).8 Therefore, new conversion coatings have been developed, and one of the most promising solutions is the Trivalent Chromium Protection coating called also as the Trivalent Chrome Process (TCP).10-14 TCP conversion coatings are formed by immersion in a solution containing Zr 4+ , Cr 3+ and F − ions, at a pH between 3.8 and 4.0. As it has already been widely discussed, the coating formation mechanism occurs by multiple chemical steps. 10,11,13,[15][16][17] The initial step involves dissolution of the aluminum oxide layer by fluorides. The removal of the oxide layer exposes the metal surface where cathodic reactions take place. Oxygen reduction reaction, and possibly hydrogen discharge, which counterbalance aluminum oxidation, consume protons and causes a pH increase at the interface between the metallic substrate and the solution, as measured by Li et al. 15 The high pH favors the precipitation of ions present in the solution, forming a hydrated layer of zirconium and chromium oxide. The thickness of the TCP layer is usually of the order of 100 nm, depending on the nature of the aluminum alloy, the concentration of the solution and the immersion time.11,12,18 ...

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XPS study of Li ion intercalation in V2O5 thin films prepared by thermal oxidation of vanadium metal

Cited by 128 publications

References 40 publications

An antioxidant nanozyme that uncovers the cytoprotective potential of vanadia nanowires

An antioxidant nanozyme that uncovers the cytoprotective potential of vanadia nanowires

X‐ray photoelectron spectroscopy study of the interaction of ultra‐thin alumina films on NiAl alloys with NaCl solutions

Role of Post-Treatment in Improved Corrosion Behavior of Trivalent Chromium Protection (TCP) Coating Deposited on Aluminum Alloy 2024-T3

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