EXAFS analysis of blue luminescence in polyoxytungstate citrate gels

Buysser, Klaartje De; Driessche, Isabel Van; Vermeir, Pieter; Thuy, Tran Thi; Schaubroeck, J.; Hoste, Serge

doi:10.1002/pssb.200880255

Cited by 7 publications

(6 citation statements)

References 18 publications

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“…The reason for the regular evolution in morphology is that the pH value has an effect on the component of the precursor solution, further affecting the morphology. According to Chemseddine et al’s report, tungstate anions (WO 4 2– ) protonize and polymerize, forming polytungstate anions in acid solution, and the structures of these anions are sensitive to the pH of the solution . At pH 1–2, anions in the solution are in the form of tungstate Y (yellow) [W 10 O 32 ] 4– .…”

Section: Resultsmentioning

confidence: 99%

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pH-Dependent Assembly of Tungsten Oxide Three-Dimensional Architectures and Their Application in Photocatalysis

Xu¹,

Jiang²,

Wang

et al. 2014

ACS Appl. Mater. Interfaces

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In this work, tungsten oxide (WO3) with three-dimensional flower-like and wheel-like architectures, based on the spontaneous aggregation of one-dimensional nanorods, were successfully fabricated by adjusting the pH of the precursor solution. The influence of pH on the morphologies of WO3 was systematically studied, and the different WO3 architectures were used to photocatalytically degrade rhodamine B. The kinetic features of photoinduced charges of as-prepared WO3 have been investigated by surface photovoltage spectroscopy and transient photovoltage techniques in detail. WO3 with wheel-like and flower-like structures possess the higher charge separation efficiency and the lower recombination rate of photoinduced charges, resulting in higher photocatalytic activity for the degradation of RhB.

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Section: Resultsmentioning

confidence: 99%

“…polymerize, forming polytungstate anions in acid solution, and the structures of these anions are sensitive to the pH of the solution 29. At pH 1−2, anions in the solution are in the form of tungstate Y (yellow) [W 10 O 32 ] 4− .…”

mentioning

confidence: 99%

pH-Dependent Assembly of Tungsten Oxide Three-Dimensional Architectures and Their Application in Photocatalysis

Xu¹,

Jiang²,

Wang

et al. 2014

ACS Appl. Mater. Interfaces

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“…These results indicate that the tungsten oxide samples have significantly different morphologies although they were prepared under similar conditions except for the different pH values. According to the literature, 42,43 ) only exists at pH values of higher than 9. With a pH in the range between 5 and 9, 44 The WO 3 nuclei, which serve as seeds, grow along the [001] direction to form small wires.…”

Section: Structure and Morphologymentioning

confidence: 99%

pH-controlled assembly of three-dimensional tungsten oxide hierarchical nanostructures for catalytic oxidation of cyclohexene to adipic acid

et al. 2016

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Tungsten oxide has a wide range of applications in chromic devices and catalysis. Effective control over the morphology of tungsten oxide remains a major challenge. Here, we present a facile pH-controlled strategy for synthesizing three-dimensional tungsten oxide architectures with different morphologies without using any templates or surfactants. These hierarchical architectures with rod-like, disk-like and spherelike morphologies are assembled from one-dimensional tungsten oxide nanowires/nanorods. The influence of the single parameter of the pH value on the morphologies and crystal structures of tungsten oxide is systematically studied. The results indicate that different polytungstate anions obtained at various pH values give rise to different crystal nuclei by a dehydration process. These crystal nuclei grow into similar phases (crystal structures) but distinct morphologies via hydrothermal treatment. Here, the similarity of the crystal structures of h-WO 3 and o-WO 3 •0.33H 2 O plays a key role in the structural transformation. Further experiments show that these three-dimensional tungsten oxide architectures display promising applications as catalysts in green chemistry for the oxidation of cyclohexene to adipic acid using an environmentally friendly oxidant (hydrogen peroxide).

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“…The reason for the color evolution in solution is that the addition of SSA changes the pH of the solution, and pH value has a great influence on the composition of the precursor solution, further influencing the morphology. In view of the many researchers’ report, WO 4 2– can protonize and polymerize in acid solution and polytungstate is formed; the structure of those anions is sensitive to the pH value of the solution. − As a general rule, WO 4 2– condenses into various types of polyoxotungstate anion. This polyoxotungstate structure depends on the [WO 6 ] octahedral structure by sharing in adjacent edges and vertexes to form a polystructure.…”

Section: Resultsmentioning

confidence: 99%

Self-Assembly Hydrothermal Synthesis of Silverton-Type Polyoxometalate-Based Photocatalysts for Enhanced Degradation

Dong

et al. 2020

Langmuir

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The synthesis of some complex polyoxometalates (POMs) is critical to develop potential photocatalysts with high catalytic activity and selectivity. Here, we address this challenge by a hydrothermal self-assembly route to obtain a novel POM-based Co4W6O21(OH)2·4H2O with a hierarchical microsphere structure. The Co4W6O21(OH)2·4H2O crystallizes in the cubic space group Im3̅ with cell parameters: a = b = c = 12.878 Å, α = β = γ = 90°, and Z = 4. The structure is further characterized by X-ray diffraction, X-ray photoelectron spectroscopy, UV–vis spectroscopy, thermogravimetric analysis, and Fourier transform infrared spectra. After depositing Ag2O nanoparticles on the 3D Co4W6O21(OH)2·4H2O microsphere by photochemical synthesis, the Co4W6O21(OH)2·4H2O/Ag2O heterojunction presents enhanced photocatalytic activity for RhB compared with P25 and pristine Ag2O. Moreover, we confirm the key role of holes for the Co4W6O21(OH)2·4H2O/Ag2O and put forward a possible mechanism for the photocatalytic degradation reaction.

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EXAFS analysis of blue luminescence in polyoxytungstate citrate gels

Cited by 7 publications

References 18 publications

pH-Dependent Assembly of Tungsten Oxide Three-Dimensional Architectures and Their Application in Photocatalysis

pH-Dependent Assembly of Tungsten Oxide Three-Dimensional Architectures and Their Application in Photocatalysis

pH-controlled assembly of three-dimensional tungsten oxide hierarchical nanostructures for catalytic oxidation of cyclohexene to adipic acid

Self-Assembly Hydrothermal Synthesis of Silverton-Type Polyoxometalate-Based Photocatalysts for Enhanced Degradation

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