Recent advances in strontium tungstate scheelite material

A novel 'plugs'-containing Al-SBA-15 material (denoted as PAS) was directly synthesized through simultaneous introducing toluene and aluminum precursor into the reaction mixture of traditional SBA-15. Such material not only featured a unique two-step desorption isotherm as conventional plugged SBA-15 synthesized using excessive siliceous precursor, and higher pore wall thickness than that of other analogous materials, but also possessed weak and medium acidic sites, which implied the PAS would offer unusual advantages such as multifunctionality to process a large variety of feed-stocks in acid-involved reaction (e.g. polymerization of tetrahydrofuran) in industrial point of view. In addition, catalytic activity of the PAS was investigated by the tetrahydrofuran (THF) polymerization reaction in the presence of acetic anhydride and compared with Al-doped MCM-41 prepared via conventional direct hydrothermal synthesis. The PAS exhibited good performance on polymerization of THF. Such result could be related to the large pore size and moderate acidic sites.

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“…The results are listed in Table II. Both synthetic conditions and analytic method of polymer were similar to those in our previous work 26 .…”

Section: Resultsmentioning

confidence: 87%

“…The flask was sealed and was set in oil bath at 313 K for 6 h. Then the catalyst was separated by filtration, and the polymer was obtained through removing the excessive THF by a rotary evaporator. The resulted polymer was analyzed by the method as reported before 26 .…”

Section: Catalytic Activity Testmentioning

confidence: 99%

Improved synthesis and study of acidic properties of ‘plugs’-containing Al-SBA-15 materials

Jia

Zhao

2010

Collect. Czech. Chem. Commun.

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“…cations are electron pair acceptors (Lewis acid), while the WO 2À 4 anions are electron pair donors (Lewis base). The reaction between these two species in solution at room temperature with different strontium salts resulted in the formation of SrWO 4 microcrystals, as shown in following equations: (1,2) strontium acetate, (3, 4) strontium nitrate, and (5, 6) strontium chloride hexahydrate.…”

Section: Synthesis Of Srwo 4 Microcrystalsmentioning

confidence: 99%

“…Strontium tungstate (SrWO 4 ) is an important material belonging to the scheelite class with excellent optical properties, especially for technological applications in solidstate lasers and stimulated Raman scattering [1,2]. Basically, this tungstate has attracted the attention of the scientific community and technological areas because of its interesting physicochemical properties, mainly including blue-green phosphors [3], photocatalytic activity for degradation of organic dyes [4,5], cathodoluminescence [6], thermal expansion [7,8], luminescence [9,10], and so on.…”

Section: Introductionmentioning

confidence: 99%

Effect of different strontium precursors on the growth process and optical properties of SrWO4 microcrystals

et al. 2015

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In this paper, an experimental study was performed on the effect induced by different strontium precursors in the growth processes and optical properties of strontium tungstate (SrWO 4) microcrystals synthesized by the co-precipitation method. The structural behavior was analyzed by means of X-ray diffractions, Rietveld refinements, Fourier transform (FT)-Raman, and FT-infrared spectroscopies. X-ray absorption near-edge structure spectra performed at the W-L 1 and L 3 edges revealed the first coordination shell around the tungsten atoms is composed of four oxygens, i.e., existence of tetrahedral [WO 4 ] clusters inside the SrWO 4 structure. Field emission scanning electron microscopy (FE-SEM) images showed the presence of pitch and longleaf pine cone-like SrWO 4 microcrystals for most of the strontium precursors employed in the synthesis. Based on these FE-SEM images, a hypothetical crystal growth mechanism was proposed to explain the origin of these microcrystals. The optical properties were investigated by ultraviolet-visible spectroscopy and photoluminescence (PL) measurements at room temperature. The different optical band gap values found for this material, depending on the type of strontium precursor, were correlated with the existence of intermediary energy levels within the forbidden region. Finally, PL profiles were associated to the degree of distortions in tetrahedral [WO 4 ] clusters.

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Morphology and Optical Properties of SrWO4 Powders Synthesized by the Coprecipitation and Polymeric Precursor Methods

Sczancoski

Mastelaro

et al. 2017

Recent Advances in Complex Functional Materials

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Recent advances in strontium tungstate scheelite material

Cited by 6 publications

References 84 publications

Improved synthesis and study of acidic properties of ‘plugs’-containing Al-SBA-15 materials

Improved synthesis and study of acidic properties of ‘plugs’-containing Al-SBA-15 materials

Effect of different strontium precursors on the growth process and optical properties of SrWO4 microcrystals

Morphology and Optical Properties of SrWO4 Powders Synthesized by the Coprecipitation and Polymeric Precursor Methods

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