The polymorphism of silver tungstate Ag<sub>2</sub>WO<sub>4</sub>

Berg, A. J. van den; Juffermans, Casper A. H.

doi:10.1107/s0021889882011510

Cited by 51 publications

(46 citation statements)

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“…[22] Amongt hose polymorphs a-Ag 2 WO 4 is thermodynamically most stable [22] and belongs to orthorhombic symmetry Pn2n. [22] Amongt hose polymorphs a-Ag 2 WO 4 is thermodynamically most stable [22] and belongs to orthorhombic symmetry Pn2n.…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, introducing am onovalentc ation such as Ag favors ac omplicated network structure of silver tungstate (Ag 2 WO 4 ), which can exhibit three different structuralp hases; a-, b-, and g-Ag 2 WO 4 . [22] Amongt hose polymorphs a-Ag 2 WO 4 is thermodynamically most stable [22] and belongs to orthorhombic symmetry Pn2n. [22,23] All tungsten atoms are six-coordinate and form WO 6 octahedra.…”

Section: Introductionmentioning

confidence: 99%

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Time‐ and Energy‐Efficient Solution Combustion Synthesis of Binary Metal Tungstate Nanoparticles with Enhanced Photocatalytic Activity

et al. 2015

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In the search for stable and efficient photocatalysts beyond TiO2 , the tungsten-based oxide semiconductors silver tungstate (Ag2 WO4 ), copper tungstate (CuWO4 ), and zinc tungstate (ZnWO4 ) were prepared using solution combustion synthesis (SCS). The tungsten precursor's influence on the product was of particular relevance to this study, and the most significant effects are highlighted. Each sample's photocatalytic activity towards methyl orange degradation was studied and benchmarked against their respective commercial oxide sample obtained by solid-state ceramic synthesis. Based on the results herein, we conclude that SCS is a time- and energy-efficient method to synthesize crystalline binary tungstate nanomaterials even without additional excessive heat treatment. As many of these photocatalysts possess excellent photocatalytic activity, the discussed synthetic strategy may open sustainable materials chemistry avenues to solar energy conversion and environmental remediation.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Time‐ and Energy‐Efficient Solution Combustion Synthesis of Binary Metal Tungstate Nanoparticles with Enhanced Photocatalytic Activity

et al. 2015

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“…In particular, Ag 2 WO 4 belongs to the oxoargentates family, 2 and it is an inorganic material containing a rich variety of polymorphs: α-orthorhombic (α-Ag 2 WO 4 ) with a space group of Pn2n, β-hexagonal with a space group of P63/m, and γ-cubic with a space group of Fd3m depending on the acid or alkaline pH range. 3,4 The orthorhombic structure of α-Ag 2 WO 4 exhibits a complex network composed of [WO 6 ] and [AgO y ] (y = 7, 6, 4, and 2) moieties as constituent clusters of this material whose internal vibration spectra provide information on the structure and order−disorder effects in crystal lattices. 5,6 This structural pattern is a key characteristic for a complete understanding of α-Ag 2 WO 4 potentialities.…”

Section: Introductionmentioning

confidence: 99%

Potentiated Electron Transference in α-Ag₂WO₄ Microcrystals with Ag Nanofilaments as Microbial Agent

et al. 2014

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This study is a framework proposal for understanding the antimicrobacterial effect of both α-Ag 2 WO 4 microcrystals (AWO) synthesized using a microwave hydrothermal (MH) method and α-Ag 2 WO 4 microcrystals with Ag metallic nanofilaments (AWO:Ag) obtained by irradiation employing an electron beam to combat against planktonic cells of methicillin-resistant Staphylococcus aureus (MRSA). These samples were characterized by X-ray diffraction (XRD), FT-Raman spectroscopy, ultraviolet visible (UV−vis) measurements, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and high resolution transmission electron microscopy (HRTEM). The results reveal that both AWO and AWO:Ag solutions have bacteriostatic and bactericidal effects, but the irradiated sample is more efficient; i.e., a 4-fold of the MRSA planktonic cells as compared to the nonirradiated sample was observed. In addition, first principles calculations were performed to obtain structural and electronic properties of AWO and metallic Ag, which provides strong quantitative support for an antimicrobacterial mechanism based on the enhancement of electron transfer processes between α-Ag 2 WO 4 and Ag nanoparticles.

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“…4,16,17 Tungsten-based oxides are an important class of materials that display wide potential functional properties, [18][19][20] speci-cally the silver tungstate (Ag 2 WO 4 ) compound, which can exhibit three different structures: a-orthorhombic, b-hexagonal, and g-cubic. [21][22][23][24][25] Recently, our research group reported a detailed study of the synthesis, structural and optical properties of hexagonal nanorod-like elongated a-Ag 2 WO 4 nanocrystals obtained by different methods.…”

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A novel ozone gas sensor based on one-dimensional (1D) α-Ag₂WO₄ nanostructures

et al. 2014

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aThis paper reports on a new ozone gas sensor based on a-Ag 2 WO 4 nanorod-like structures. Electrical resistance measurements proved the efficiency of a-Ag 2 WO 4 nanorods, which rendered good sensitivity even for a low ozone concentration (80 ppb), a fast response and a short recovery time at 300 C, demonstrating great potential for a variety of applications.Metal semiconducting oxides have drawn the interest of many researchers due to their wide range of applications, especially as gas sensing materials. 1-5 Among them, one-dimensional (1-D) semiconductor nanostructures have been proposed as very interesting materials, especially as gas sensor devices.6-12 It is well known that several technological applications of nanostructured materials are directly related to the morphology, particle size, crystalline phase and activity of specic crystalline planes strictly dependent on synthesis methods. 4,[13][14][15] In particular, the relationship between morphology and gas sensing properties has been well established. 4,16,17Tungsten-based oxides are an important class of materials that display wide potential functional properties, 18-20 speci-cally the silver tungstate (Ag 2 WO 4 ) compound, which can exhibit three different structures: a-orthorhombic, b-hexagonal, and g-cubic.21-25 Recently, our research group reported a detailed study of the synthesis, structural and optical properties of hexagonal nanorod-like elongated a-Ag 2 WO 4 nanocrystals obtained by different methods. 26-28Ozone (O 3 ) is an oxidizing gas used in many technological applications in different areas, such as the food industry, drinking-water treatment, medicine, microelectronic cleaning processes, and others.29,34-39 For example, ozone has been employed as a powerful drinking-water disinfectant and oxidant. 34,35,40 On the other hand, when the ozone level in an atmosphere exceeds a certain threshold value, the exposure to this gas becomes hazardous to human health and can cause serious health problems (e.g. headache, burning eyes, respiratory irritation and lung damage).34,41 The European Guidelines (2002/3/EG) recommend avoiding exposure to ozone levels above 120 ppb.41 Such arguments support the requirement for the determination and continuous monitoring of ozone levels. 3,29,41Gas sensing properties are evaluated in terms of operating temperature, sensitivity, response time, recovery time and stability.29-33 SnO 2 , In 2 O 3 and WO 3 compounds have been considered the most promising ozone gas sensors. 29-33To the best of our knowledge, to date the gas sensing properties of a-Ag 2 WO 4 nanocrystals have never been evaluated.Here, we report the sensing properties of 1-D a-Ag 2 WO 4 nanorod-like structures obtained by the microwave-assisted hydrothermal (MAH) method.42-46 Because of such properties, nanorods are potential candidates for practical applications as ozone gas sensors.The crystalline phase of the as-obtained a-Ag 2 WO 4 sample was analyzed by X-ray diffraction measurement and all reec-tions were indexed to an orthorhombic struc...

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The polymorphism of silver tungstate Ag₂WO₄

Cited by 51 publications

References 1 publication

Time‐ and Energy‐Efficient Solution Combustion Synthesis of Binary Metal Tungstate Nanoparticles with Enhanced Photocatalytic Activity

Time‐ and Energy‐Efficient Solution Combustion Synthesis of Binary Metal Tungstate Nanoparticles with Enhanced Photocatalytic Activity

Potentiated Electron Transference in α-Ag₂WO₄ Microcrystals with Ag Nanofilaments as Microbial Agent

A novel ozone gas sensor based on one-dimensional (1D) α-Ag₂WO₄ nanostructures

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The polymorphism of silver tungstate Ag2WO4

Cited by 51 publications

References 1 publication

Time‐ and Energy‐Efficient Solution Combustion Synthesis of Binary Metal Tungstate Nanoparticles with Enhanced Photocatalytic Activity

Time‐ and Energy‐Efficient Solution Combustion Synthesis of Binary Metal Tungstate Nanoparticles with Enhanced Photocatalytic Activity

Potentiated Electron Transference in α-Ag2WO4 Microcrystals with Ag Nanofilaments as Microbial Agent

A novel ozone gas sensor based on one-dimensional (1D) α-Ag2WO4 nanostructures

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Product

Resources

About

The polymorphism of silver tungstate Ag₂WO₄

Potentiated Electron Transference in α-Ag₂WO₄ Microcrystals with Ag Nanofilaments as Microbial Agent

A novel ozone gas sensor based on one-dimensional (1D) α-Ag₂WO₄ nanostructures