A Survey of Applications of Polyoxometalates

Katsoulis, Dimitris E.

doi:10.1021/cr960398a

Cited by 1,196 publications

(675 citation statements)

References 132 publications

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“…Electrochemistry in the absence of external electrolyte is important because of its potential applications in different fields, including catalysis, materials science, and medicine [1,2]. The materials used for solid-state voltammetry should contain not only reactive redox species, through which fast reversible electron transfer is possible, but also fairly large amounts of mobile counter cations to keep the electroneutrality.…”

Section: Introductionmentioning

confidence: 99%

“…Generally, Keggin-type polyoxometalates have a central XO 4 (X = B, Si, Ge, P, As) tetrahedron surrounded by 12 MO 6 octahedrons arranged in four groups of three-octahedral subunits, M 3 O 13 . These four groups are linked by their corresponding edges to each other and to the central XO 4 tetrahedron [1,2,27]. The overall POMs charge depends on its heteroatoms and the nature of transition metals.…”

Section: Introductionmentioning

confidence: 99%

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Solid-state electrochemical behavior of Keggin-type borotungstic acid single crystal

Adamczyk

Miecznikowski

2013

J Solid State Electrochem

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We demonstrate the electrochemical characteristics of the, poorly described in the literature, mixed-valence proton conducting solid borotungstic acid single crystal, H 5 BW 12 O 40 xH 2 O, in the absence of liquid electrolyte phase. We performed electrochemical measurements in an all-solid cell with a gold fiber ultramicrodisk (diameter 10, 25, and 40 μm) working electrode, a silver semi-reference disk electrode, and a glassy carbon ring counter electrode. Diagnostic experiments at different scan rates aimed at probing the model of mass transport and potential kinetic limitations. Such bulk parameters as the effective diffusion coefficient of charge propagation and the concentration of mixed-valence redox centers were determined by two methods. The first method is based on the analysis of both Cottrellian and steady-state currents (the mixed-regimes method), and the second method provides the true diffusion coefficient (transport coefficient free of the migration influence) for both the substrate and the product of the electrode reaction. Together, these methods constitute a double potential step chronoamperometry experiment. The data obtained with these electrochemical experiments (effective diffusion coefficients, concentration of mixed-valence redox centers, etc.) can support the results obtained with other techniques (XRD, FTIR, and TGA).

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Solid-state electrochemical behavior of Keggin-type borotungstic acid single crystal

Adamczyk

Miecznikowski

2013

J Solid State Electrochem

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“…The catalytic application of HPAs, polyoxometalates (POMs) (12,(14)(15)(16)(17) as efficient homogeneous or heterogeneous solid acids catalysts have been recognized and established both by successful large-scale applications in industry and promising laboratory results (12,(18)(19)(20).…”

Section: Hpasmentioning

confidence: 99%

Heteropoly acids-catalyzed organic reactions in water: doubly green reactions

Heravi

Fard

Faghihi

2013

Green Chemistry Letters and Reviews

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The organic reactions in water, as the most significant green solvent, have attracted much attention due to their unique properties over conventional organic ones. In the catalytic area, heteropoly acids (HPAs) are also promising green solid acids to replace environmentally harmful liquid acid catalysts. Herein, we wish to report the organic reactions catalyzed by HPAs, their salt, and polyoxometalates (POMs) in aqueous systems.

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“…According to previous theoretical and computational studies [33], the V atom is in the primary structure of the classical Keggin-type as a V-OH group, and it lowers its average oxidation state when present as VO − PyH + species. In addition, it is proposed that the organic π electrons may extend their conjugation to the inorganic framework and thus modify the redox properties of the cluster [34,35]. IR spectra in Fig.…”

Section: Catalytic Activitymentioning

confidence: 99%

Keggin heteropolycompounds as catalysts for liquid-phase oxidation of sulfides to sulfoxides/sulfones by hydrogen peroxide

Romanelli

Villabrille

Cáceres

et al. 2011

Catalysis Communications

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H 4 PMo 11 VO 40 , H 5 PMo 10 V 2 O 40 and H 9 PMo 6 V 6 O 40 acids and an acidic pyridinium salt of H 4 PMo 11 VO 40 were synthesized. They were characterized by FT-IR and the variations of their acid properties were determined by titration with n-butylamine. They proved to be highly active and selective catalysts for the hydrogen peroxide oxidation of methyl phenyl sulfide to the corresponding sulfoxide or sulfone. The conversion and selectivity results may be explained in terms of the co-existence of acidic and oxidative properties in the catalysts. On the other hand, a convenient catalytic homogeneous procedure has been found to oxidize different sulfides to sulfoxides or sulfones, with 35% aqueous H 2 O 2 , using (PyH)H 3 PMo 11 VO 40 as catalyst. The oxidation reaction is carried out at room temperature for sulfoxides or 40°C for sulfones and requires a short time. The sulfoxides or sulfones were obtained with excellent yields by controlling the amount of H 2 O 2 .

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A Survey of Applications of Polyoxometalates

Cited by 1,196 publications

References 132 publications

Solid-state electrochemical behavior of Keggin-type borotungstic acid single crystal

Solid-state electrochemical behavior of Keggin-type borotungstic acid single crystal

Heteropoly acids-catalyzed organic reactions in water: doubly green reactions

Keggin heteropolycompounds as catalysts for liquid-phase oxidation of sulfides to sulfoxides/sulfones by hydrogen peroxide

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