Stabilization of Alkali Promoters in Structure of the Iron Oxide Dehydrogenation Catalysts

Anikanova, L. G.; Dvoretskii, N. V.

doi:10.18412/1816-0387-2016-1-29-36

Cited by 5 publications

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“…Moreover, the mobility of potassium is related to the ease of alkaline promoter emission. It also concerns with the corrosion resistance of β″-polyferrite -the ability of the catalyst to function despite unfavourable effects of the reaction medium and the presence of catalytic poisons [5]. Ca 2+ or Sr 2+ ions entering the interblock space reduce the mobility of alkali promoter ions and prevent its emission during catalyst operation.…”

Section: Fig 2 Placement Of Doping Doubly Charged Ions In the Unit Ce...mentioning

confidence: 99%

“…Moreover, the required information can be obtained without labour-intensive and costly catalytic tests. The cationic conductivity of polyferrite is directly related to the migration and emission of the alkaline promoter [5]. The cationic conductivity data of K-βʺFe2O3 can predict the corrosion resistance of the catalytically active phase and catalyst lifetime.…”

Section: Introductionmentioning

confidence: 99%

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Electrical conductivity of potassium polyferrite doped with doubly charged cations

Dvoreckaya,

Anikanova,

Sudzilovskaya

et al. 2024

From Chemistry Towards Technology Step-by-Step

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To clarify the charge compensation mechanism and the way of alloying additives placement, the authors synthesised samples of potassium βʺ-polyferrites with a wide range of mole fraction of introduced doubly charged cations. For these samples, the authors measured the electronic conductivity, cationic conductivity, and performed X-ray diffraction (XRD) analysis. The authors identified the charge compensation mechanism in potassium β″-polyferrite when doped with divalent ions of calcium, strontium, magnesium, and zinc. The charge compensation mechanisms differ depending on the radius of the introduced doubly charged ion. The results of cationic conductivity measurements of potassium β″-polyferrites show the mobility reduction of large calcium and strontium cations of potassium ions. Such additives are quite promising for improving the mechanical strength and thermal stability of the catalyst granules. They also increase the chemical stability of the contact granules. Corrosion resistance of pellets is a critical parameter. It determines the period of effective functioning of the catalyst. The data on electronic conductivity allow one to conclude that the introduction of Mg2+, Zn2+ cations sharply reduces the electron exchange in the structure of potassium β″-polyferrite. This should inevitably cause deactivation of the catalyst, while Ca2+ and Sr2+ ions do not reduce the electron transfer rate. Moreover, using the proposed approach will intensify the research process.

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Section: Fig 2 Placement Of Doping Doubly Charged Ions In the Unit Ce...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Electrical conductivity of potassium polyferrite doped with doubly charged cations

Dvoreckaya,

Anikanova,

Sudzilovskaya

et al. 2024

From Chemistry Towards Technology Step-by-Step

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Influence of Powdered Cellulose and Charge Preparation Procedure on the Phase Composition and Characteristics of the Iron-Potassium Oxide Material

et al. 2019

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The effect of doubly charged ion additives on the activity and chemical stability of catalytically active potassium ferrites

Anikanova

Dvoretskii

2020

Kat.v.prom.

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To reveal the effect of the dopant doubly charged ion size on the catalytic properties, samples of potassium polyferrites of β′′-alumina type with the composition K2FeII1-q MqFeIII 10O17, where M = Mg, Zn, and K2–2qFeIIMqFeIII 10O17, where M = Ca, Sr, and q = 0.4, were synthesized. The mechanism of action of the introduced doubly charged cations on the activity, selectivity and corrosion resistance of potassium β′′-polyferrite was elucidated. It was shown for the first time that the size of doubly charged cations determines their position in the structure of β′′-polyferrite: they either enter the spinel-like moiety and substitute Fe2+ ions, or substitute potassium in the intermoiety space. The introduction of Mg2+ and Zn2+ ions dramatically reduces the catalytic activity and selectivity of β′′-polyferrite. The application of such additives is undesirable. Small amounts of Ca2+ and Sr2+ cations significantly improve the corrosion resistance of the catalyst by decreasing the mobility of potassium ions within the cation-conducting layer.

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Stabilization of Alkali Promoters in Structure of the Iron Oxide Dehydrogenation Catalysts

Cited by 5 publications

References 0 publications

Electrical conductivity of potassium polyferrite doped with doubly charged cations

Electrical conductivity of potassium polyferrite doped with doubly charged cations

Influence of Powdered Cellulose and Charge Preparation Procedure on the Phase Composition and Characteristics of the Iron-Potassium Oxide Material

The effect of doubly charged ion additives on the activity and chemical stability of catalytically active potassium ferrites

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