Revised pourbaix diagrams for iron at 25–300 °C

Beverskog, B.; Puigdomènech, I.

doi:10.1016/s0010-938x(96)00067-4

Cited by 403 publications

(261 citation statements)

References 49 publications

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“…[16] [16] (DG°3 83K [110°C] < À36.49 kJ/mol). [48][49][50][51][52] In addition, a few small powdery electroreduction-generated iron grains are found in the reaction interface (the inset in Figure 14(a)), which suggests that the solid state electroreduction mechanism (Reactions [1] and [2]), i.e., Fe 2 O 3 fi Fe 3 O 4 fi Fe, is likely to present in the electroreduction process. The electroreduction-generated oxygen ion could then react with H 2 O to form OH À , i.e., O 2À + H 2 O fi 2OH À .…”

Section: Influence Of the Electroreduction Time On The Electroredumentioning

confidence: 99%

“…[15] The theoretical decomposition potentials (E°) for Reactions [1] through [3] have been calculated from the reported thermodynamic data. [48][49][50][51][52] …”

Section: Influence Of the Electroreduction Time On The Electroredumentioning

confidence: 99%

“…The standard Gibbs free energy changes (DG°) or the theoretical decomposition potentials (E°) for Reactions [4] through [9] have been calculated based on the reported thermodynamic data. [48][49][50][51][52] More details about the reaction mechanisms of the electrodeposition of iron from Fe 2 O 3 and NaFeO 2 precursors in aqueous NaOH solution can be found in our recent work. [56] Therefore, during the electroreduction process in this experiment, Fe 2 O 3 precursor and the electroreduction-generated Fe 3 O 4 and/or NaFeO 2 intermediates surrounded by aqueous NaOH solution would dissolve in the nearby electrolyte simultaneously, and then redeposit on the preformed iron to form dendritic crystals in the reaction front area immediately (as schematically shown in Figure 14(b)).…”

Section: Solid State Electroreduction Mechanismmentioning

confidence: 99%

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Electroreduction of Iron(III) Oxide Pellets to Iron in Alkaline Media: A Typical Shrinking-Core Reaction Process

Zou

et al. 2015

Metall Mater Trans B

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Low temperature electrochemical reduction of iron(III) oxide to iron in a strongly alkaline solution has been systematically investigated in this article. The facile electrochemical process was carried out in 50 to 70 wt pct aqueous NaOH solution at 383 K (110°C) and 1.7 V. The preformed spherical Fe 2 O 3 pellets with porous structures were used directly as precursors for the electrolytic production of iron. The influences of the experimental parameters on the electroreduction process and the characteristics of the iron products as well as the reaction mechanisms were investigated. The results show that the precursor's pre-sintering process and the concentration of NaOH aqueous electrolyte have significant influences on the electroreduction process. The electroreduction-generated spherical metallic iron layer comprising dendritic iron crystals is first formed on the surface of Fe 2 O 3 pellet precursor and then extends gradually into the pellet's interior along the radial direction. The electroreduction process is confirmed to be a typical shrinking-core reaction process. The direct solid state electroreduction mechanism and the dissolution-electrodeposition mechanism coexist in the electrochemical process. The experimental observations suggest that the dissolution-electrodeposition mechanism appears to be the dominant mechanism under the experimental conditions employed in this study. This facile process may open a new green electricitybased route for the production of dendritic iron crystals from iron(III) oxide in alkaline media.

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Section: Influence Of the Electroreduction Time On The Electroredumentioning

confidence: 99%

“…[15] The theoretical decomposition potentials (E°) for Reactions [1] through [3] have been calculated from the reported thermodynamic data. [48][49][50][51][52] …”

Section: Influence Of the Electroreduction Time On The Electroredumentioning

confidence: 99%

Section: Solid State Electroreduction Mechanismmentioning

confidence: 99%

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Electroreduction of Iron(III) Oxide Pellets to Iron in Alkaline Media: A Typical Shrinking-Core Reaction Process

Zou

et al. 2015

Metall Mater Trans B

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“…e-mail: dcontrer@udec.cl (13) In this compound Fe 2+ is oxidized through a inner sphere mechanisms ( Figure 3). Keenan et al (14) propose a hydrogen peroxo-complex [Fe(H 2 O 2 )] 2+ as intermediary.…”

Section: Iron Speciation and Fenton Reactionmentioning

confidence: 99%

Fenton Reaction Driven by Iron Ligands

Salgado

Melín

Contreras

et al. 2013

J. Chil. Chem. Soc.

100

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One of the most important sources of reactive oxygen species (ROS) in biological systems is the Fenton reaction. In this, the Fe 2+ or Fe 3+ reacts with H 2 O 2 to produce ROS as the hydroxyl radical (•OH), superoxide radical (O 2 •-) and singlet oxygen ( 1 O 2 ). The main ROS, responsible for the high oxidizing power of the Fenton reaction, is not clear. Some authors claim that the principal reactive species is •OH, while others propose a ferryl specie (Fe 4+ or [FeO] 2+ ) (1,2) . Recently, have been proposed that the kind of reaction species produced depends mainly of pH and the iron composition of the coordination sphere. This is highlighted for Fe 3+ , because in mono and (some) bis-complexes Fe 3+ is reduced to Fe 2+ and there are some positions occupied by water or hydroxide ligands, readily to be exchanged by H 2 O 2 . On the other hand, in tris-complexes there are not any positions occupied by water or hydroxide, avoiding the formation of peroxo-complexes, necessary for Fenton or Fenton like reaction.The 1,2-dihydroxybenzenes (DHBs) have been described as modulators of Fenton reaction. The DHBs driven Fenton reaction have been used for environmental applications as an advanced oxidation process. Furthermore, these systems participate in different biological process, as the wood biodegradation by fungi and oxidative stress in neurodegenerative diseases.In this review, the effect of 1,2-dihydroxybenzenes on the activated species production by the Fenton and Fenton like reaction will be discussed and its participation in different systems.

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“…Na podstawie dostępnych w literaturze [7,8] diagramów Pourbaix, można stwierdzić, że możliwy jest taki dobór warunków reakcji elektrochemicznej -poprzez dobór potencjału anody i pH elektrolitu -aby na powierzchni przedmiotu obrabianego (anody) wytworzyła się cienka warstwa trudno rozpuszczalnych i nieprzewodzących prądu elektrycznego tlenków żelaza (najczęściej Fe 2 O 3 ) -tzw. warstwa pasywna.…”

Section: Koncepcja Mikrotoczenia Wspomaganego Elektrochemicznieunclassified

Electrochemically assisted microturning process

Grabowski¹

2015

Mechanik

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Revised pourbaix diagrams for iron at 25–300 °C

Cited by 403 publications

References 49 publications

Electroreduction of Iron(III) Oxide Pellets to Iron in Alkaline Media: A Typical Shrinking-Core Reaction Process

Electroreduction of Iron(III) Oxide Pellets to Iron in Alkaline Media: A Typical Shrinking-Core Reaction Process

Fenton Reaction Driven by Iron Ligands

Electrochemically assisted microturning process

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