The Products of the Anodic Oxidation of an Iron Electrode in Alkaline Solution

Silver, H. Graham; Lekas, Elfriede

doi:10.1149/1.2407439

Cited by 55 publications

(25 citation statements)

References 10 publications

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“…For 5-FeOOH the main band 670 cm -1 is the same as for Fe304, hence in case of low signals the assignment of spectra can be equivocal. This compound was found at the potential of peak III with the use of x-ray diffraction (6) and Raman spectroscopy (40). The spectrum for peak II did not show any characteristic Raman bands, whereas the spectrum for peak III exhibited a distinct band 670cm -] and a slight band 400 cm -t. The band 670 cm =1 is characteristic both for Fe304 and ~-FeOOH, whereas band 400 cm -1 is characteristic for 8-FeOOH.…”

Section: Resultsmentioning

confidence: 96%

Use of Raman Spectroscopy and Rotating Split Ring Disk Electrode for Identification of Surface Layers on Iron in 1M NaOH

Goff

Flis

Boucherit

et al. 1990

J. Electrochem. Soc.

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In situ Raman spectroscopy and rotating split-ring disk electrode were used to identify products formed on iron in 1M NaOH at 22~ at various peaks of cyclic voltammograms. The peak at the most active potential of the cathodic reverse sweep has been ascribed to the reduction of Fe304 to Fe 2+ species: this peak suggested that Fe304 started to form at the first peak of anodic sweep and that it built up at nobler potentials. The Raman spectroscopy has revealed the formation of Fe304 in the wide range of potentials, of ~-FeOOH and/or Fe304 at peak III of anodic sweep, and of ~]-Fe203 after prolonged polarization at a potential of 0.27V (SCE). Rapid cycling or long exposure resulted in the formation of Fe304 and a-FeOOH. It is suggested that the passivating film on iron in 1M NaOH is composed of an inner Fe304 layer and of an outer layer containing other products.The electrochemistry and corrosion of iron and carbon steel in hydroxide solutions have been studied by many authors (1-20). Technological importance of the iron/ hydroxide system is associated with alkaline batteries, with hydrolysis of water, and with corrosion in hot alkalies. Extensive studies have been devoted particularly to the passivation and composition of passive films.Hydrolysis of soluble corrosion products on iron in alkalies leads to the formation of Fe(OH)2 (21). Eventually there are formed Fe304 (22), ~-Fe203 (23, 24), ~-FeOOH (21, 23) and other oxyhydroxides (25). ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 192.236.36.29 Downloaded on 2015-04-11 to IP

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Section: Resultsmentioning

confidence: 96%

Use of Raman Spectroscopy and Rotating Split Ring Disk Electrode for Identification of Surface Layers on Iron in 1M NaOH

Goff

Flis

Boucherit

et al. 1990

J. Electrochem. Soc.

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“…Information on the addition of other ions or salts, and their effects, is scarce. Li + ion addition was studied by several authors [120][121][122] and, although their results were not completely in agreement, lithium was concluded to have a strong negative influence on the structure of the surface anode layer. A more detailed study by Bouzek et al [54] found that a 5 M LiOH solution was unsuitable for providing sufficient current yields in the temperature range of 20-40 • C. Deininger [105] referred to the presence of halides causing an increase in the rate of iron surface corrosion by permeating and weakening the protective surface layer at the anode.…”

Section: Electrolyte Compositionmentioning

confidence: 99%

Research progress in the electrochemical synthesis of ferrate(VI)

Mácová

Bouzek

Hı́veš

et al. 2009

Electrochimica Acta

140

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“…This could as well be due to repeated cycling of the iron electrode as reported in the literature. 18 The increase in intensity of the peaks due to magnetite suggests that ferrous hydroxide could be easily oxidized to magnetite. In other words, PAM Fe electrodes without bismuth sulfide additives are easily passivated.…”

Section: Resultsmentioning

confidence: 99%

In Situ Crystallographic Probing on Ameliorating Effect of Sulfide Additives and Carbon Grafting in Iron Electrodes

Ravikumar

Rajan

Sampath

et al. 2015

J. Electrochem. Soc.

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Beneficial effects of carbon grafting into the iron active material for rechargeable alkaline-iron-electrodes with and without Bi 2 S 3 additive is probed by in situ X-ray diffraction in conjunction with Extended X-ray Absorption Fine Structure (EXAFS) and electrochemistry. EXAFS data unravel that the composition of pristine active material (PAM) for iron electrodes comprises 87% of magnetite and 13% of α-iron while carbon-grafted active material comprises 60% of magnetite and 40% of α-iron. In situ XRD patterns are recorded using a specially designed electrochemical cell. XRD data reflect that magnetite present in PAM iron electrode, without bismuth sulfide additive, is not reduced during charging while PAM iron electrode with bismuth sulfide additive is partially reduced to α-Fe/Fe(OH) 2 . Interestingly, carbon-grafted-iron electrodes with bismuth sulfide exhibit complete conversion of active material to α-Fe/Fe(OH) 2 . The ameliorating effect of carbon grafting is substantiated by kinetic parameters obtained from steady-state potentiostatic polarization and Tafel plots. The mechanism for iron-electrode charge -discharge reactions are discussed in the light of the potential -pH diagrams for Fe -H 2 O, S -H 2 O and FeS ads -H 2 O systems and it is surmised that carbon grafting into iron active material promotes its electrochemical utilization.

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The Products of the Anodic Oxidation of an Iron Electrode in Alkaline Solution

Cited by 55 publications

References 10 publications

Use of Raman Spectroscopy and Rotating Split Ring Disk Electrode for Identification of Surface Layers on Iron in 1M NaOH

Use of Raman Spectroscopy and Rotating Split Ring Disk Electrode for Identification of Surface Layers on Iron in 1M NaOH

Research progress in the electrochemical synthesis of ferrate(VI)

In Situ Crystallographic Probing on Ameliorating Effect of Sulfide Additives and Carbon Grafting in Iron Electrodes

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