Influence of the thermal treatment in the crystallization of NiWO4 and ZnWO4

Oliveira, André Luiz Menezes de; Ferreira, J. M.; Silva, Márcia R. S.; Souza, Soraia Carvalho de; Vieira, F. T. G.; Longo, Elson; Souza, A. G.; Santos, I. M. G.

doi:10.1007/s10973-009-0244-8

Cited by 61 publications

(41 citation statements)

References 27 publications

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“…The band at 1.47 eV can be assigned to the presence of Ni 2+ O 4 arising from Frenkel defects with dislocation of Ni 2+ from the octahedral to tetrahedral sites. This result is in agreement with that of de Oliveira et al [37]. …”

Section: Resultssupporting

confidence: 94%

“…Four bands observed from the NiWO 4 sample at both UV and visible range (Figure 5(b)) are due to the oxidation state of the cations [37]. Cimino et al [38] had reported that absorption bands at 1.21, 1.65-1.74, 2.00-2.11, 2.83-2.88 and 3.35 eV from Ni 2+ O 6 are due to the transition from 3 A 2g to the excited states 3 T 2g , 1 E g , 3 T 1g , 1 T 2g , and 3 T 1g , respectively.…”

Section: Resultsmentioning

confidence: 99%

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Structural and optical characterization of metal tungstates (MWO4; M=Ni, Ba, Bi) synthesized by a sucrose-templated method

Zawawi

Yahya

Hassan

et al. 2013

Chemistry Central Journal

134

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BackgroundMetal tungstates have attracted much attention due to their interesting structural and photoluminescence properties. Depending on the size of the bivalent cation present, the metal tungstates will adopt structures with different phases. In this work, three different phases of metal tungstates MWO4 (M= Ba, Ni and Bi) were synthesized via the sucrose templated method.ResultsThe powders of BaWO4 (tetragonal), NiWO4 (monoclinic) and Bi2WO6 (orthorhombic) formed after calcination temperatures of 750, 650 and 600°C for 4 h respectively are found to be crystalline and exist in their pure phase. Based on Scherrer estimation, their crystallite size are of nanosized. BET results showed NiWO4 has the highest surface area. BaWO4 exhibited less Raman vibrations than the NiWO4 because of the increased lattice symmetry but Bi2WO6 showed almost the same Raman vibrations as BaWO4. From the UV-vis spectra, the band gap transition of the metal tungstates are of the order of BaWO4 > Bi2WO6 > NiWO4. Broad blue-green emission peaks were detected in photoluminescence spectra and the results showed the great dependence on morphology, crystallinity and size of the metal tungstates.ConclusionThree different phases of metal tungstates of BaWO4 (scheelite), NiWO4 (wolframite) and Bi2WO6 (perovskite layer) in their pure phase were successfully prepared by the simple and economical sucrose-templated method. The highest surface area is exhibited by NiWO4 while largest band gap is shown by BaWO4. These materials showed promising optical properties.

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Section: Resultssupporting

confidence: 94%

Section: Resultsmentioning

confidence: 99%

Structural and optical characterization of metal tungstates (MWO4; M=Ni, Ba, Bi) synthesized by a sucrose-templated method

Zawawi

Yahya

Hassan

et al. 2013

Chemistry Central Journal

134

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“…8,50,51 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 different mechanism for their formation of cubical SnWO 4 microcrystals in CTAB surfactant media. 30 They observed that β-SnWO 4 having NaCl like crystal structure grow more along the to Sn +4 .…”

Section: X-ray Photoelectron Spectroscopic (Xps) Analysismentioning

confidence: 99%

Microwave Synthesis of SnWO₄ Nanoassemblies on DNA Scaffold: A Novel Material for High Performance Supercapacitor and as Catalyst for Butanol Oxidation

Ede

Kundu

2015

ACS Sustainable Chem. Eng.

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Self-assembled, aggregated SnWO 4 nano-assemblies are formed by the reaction ofSn(II) salt and Na 2 WO 4 .2H 2 O in the presence of DNA under microwave heating within six minutes. We have emphasized the natural properties of DNA with its ability to scaffold SnWO 4 nano-assemblies and examined the role of starting reagents on the particles morphology. The diameter of the individual particles is ultra-small and varies from ~ 1-2.5 nm. The potentiality of the SnWO 4 nano-assemblies has been tested for the first time in two different applications, such as an anode material in electrochemical supercapacitor studies and as a catalyst for the oxidation of butanol to butanoic acid. From supercapacitor study, it was observed that SnWO 4 nano-assemblies with different sizes showed different specific capacitance (C s ) values and the highest C s value was observed for SnWO 4 nano-assemblies having small size of the individual particles. The highest C s value of 242 F g -1 was observed at a scan rate of 5 mV s -1 for small size SnWO 4 nano-assemblies. The capacitor shows an excellent long cycle life along with 85% retention of C s value even after 4000 consecutive times of cycling at a current density of 10 mAcm -2 . From the catalysis studies, it was observed that SnWO 4 nano-assemblies acted as a potential catalyst for the oxidation of butanol to butanoic acid using eco-friendly hydrogen peroxide as an oxidant with 100 % product selectivity. Other than catalysis and supercapacitor, in futuristic, the material can further be used in sensor, visible light photo-catalysis and energy related applications.Research on nanomaterials, mainly nanoparticles (NPs) has been focused on the assembly strategies to control the specific arrangement of NPs. The morphology controlled synthesis of zero and 1-dimensional (1-D) inorganic nanomaterials have attracted significant interest due to the importance of the geometrical forms of materials in determining their widely varying properties at nanoscale. 1-3 During last few years, a bunch of techniques had been developed for the successful generation of self-assembled NPs into ordered nanostructures. However, there are very few techniques available to organize nanomaterials in a precise 1-D pattern. The 'bottom up' approach and the wet-chemical synthesis have been found to be the most easy and facile way to synthesize self-assemble nanomaterials in 1-D patterns in a short time scale. While considering metal oxide nanomaterials in general, they have been extensively studied owing to their unique magnetic, catalytic and Energy storage properties across a broad range of fundamental and technological potential. In particular, the fields like Energy storage and in catalysis. Electrochemical Supercapacitors show the desirable characteristics of high power density, fast charging, excellent cyclic stability, small size and low mass, when compared with batteries and fuel cells, make them one of the most promising candidates for next generation power devices. 4-7 In general, most commercially available ...

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“…The vibrational properties of NiWO 4 in the mid-infrared range 400-2000 cm −1 were studied previously in [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Synchrotron-based far-infrared spectroscopy of nickel tungstate

Kalinko

Kuzmin

Roy

et al. 2016

Low Temperature Physics

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Influence of the thermal treatment in the crystallization of NiWO4 and ZnWO4

Cited by 61 publications

References 27 publications

Structural and optical characterization of metal tungstates (MWO4; M=Ni, Ba, Bi) synthesized by a sucrose-templated method

Structural and optical characterization of metal tungstates (MWO4; M=Ni, Ba, Bi) synthesized by a sucrose-templated method

Microwave Synthesis of SnWO₄ Nanoassemblies on DNA Scaffold: A Novel Material for High Performance Supercapacitor and as Catalyst for Butanol Oxidation

Synchrotron-based far-infrared spectroscopy of nickel tungstate

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Influence of the thermal treatment in the crystallization of NiWO4 and ZnWO4

Cited by 61 publications

References 27 publications

Structural and optical characterization of metal tungstates (MWO4; M=Ni, Ba, Bi) synthesized by a sucrose-templated method

Structural and optical characterization of metal tungstates (MWO4; M=Ni, Ba, Bi) synthesized by a sucrose-templated method

Microwave Synthesis of SnWO4 Nanoassemblies on DNA Scaffold: A Novel Material for High Performance Supercapacitor and as Catalyst for Butanol Oxidation

Synchrotron-based far-infrared spectroscopy of nickel tungstate

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Microwave Synthesis of SnWO₄ Nanoassemblies on DNA Scaffold: A Novel Material for High Performance Supercapacitor and as Catalyst for Butanol Oxidation