Preparation of bulk and supported heteropolyacid salts

Soled, S.; Miseo, S.; Mcvicker, G. B.; Gates, William E.; Gutiérrez, Alejandro García; Paes, Juliana Lobo

doi:10.1016/s0920-5861(96)00235-0

Cited by 90 publications

(48 citation statements)

References 14 publications

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“…HPA show a very strong Bronsted acidity as solid electrolytes [1][2][3][4] and can be identified as a general formula [XM 12 O 40 ] x -8 , where X is the central heteroatom (Si …”

Section: Introductionmentioning

confidence: 99%

Phosphotungstic Acid Supported on a Nanopowdered ZrO₂ as a Filler in Nafion‐Based Membranes for Polymer Electrolyte Fuel Cells

et al. 2008

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An inorganic filler prepared by impregnation of phosphotungstic heteropolyacid on zirconia (HPW/Zr) was developed to be inserted into a perfluorosulphonic polymer matrix for a polymer electrolyte fuel cell (PEFC) operating at a medium temperature (80–120 °C) and low relative humidity (RH). Two different phosphotungstic acid (PWA) loadings (30 and 45% w/w) were anchored on a nanopowdered ZrO2. Such compounds were characterised by different techniques: differential scanning calorimetry (DSC), X‐ray diffraction (XRD), energy dispersive X‐ray analysis (EDX) and porosity and surface area by Brunauer–Emmett–Teller (BET), to verify the introduction and anchorage of PWA on ZrO2. Two composite Nafion membranes were prepared and characterised in terms of chemical–physical characteristics and electrochemical tests. Thermogravimetric analysis (TGA) provided evidence that HPW/Zr had been incorporated into composite membranes and it was not eluted. A good proton conductivity of about 6 × 10–3 S cm–1 at 120 °C and 25% RH was recorded.Accelerated in situ ageing tests highlighted a good electrochemical stability (more than 150 cycles at 90 °C with dry gases) of the composite membranes with a slow decay and a reasonable integrity of the analysed membrane‐electrodes assembly (MEA). Finally, a post‐mortem SEM–EDX analysis on MEAs confirmed the presence of HPW/Zr in the membrane after the in situ testing.

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“…HPA show a very strong Bronsted acidity as solid electrolytes [1][2][3][4] and can be identified as a general formula [XM 12 O 40 ] x -8 , where X is the central heteroatom (Si …”

Section: Introductionmentioning

confidence: 99%

Phosphotungstic Acid Supported on a Nanopowdered ZrO₂ as a Filler in Nafion‐Based Membranes for Polymer Electrolyte Fuel Cells

et al. 2008

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“…Cesium salt was prepared by the dropwise addition of a stoichiometric quantity of aqueous Cs 2 CO 3 (0.47 M) to an aqueous solution of H 3 PW 12 O 40 (0.75 M) at 40°C with continuous stirring [28]. The precipitate obtained was dried for 48 h in an oven at 100°C and calcined at 500°C for 5 h. A series of catalysts are prepared by changing the molar ratio from 0 to 5 of Sn by impregnation method.…”

Section: Experimental Catalyst Preparationmentioning

confidence: 99%

Synthesis and characterization of Cs-exchanged heteropolyacid catalysts functionalized with Sn for carbonolysis of glycerol to glycerol carbonate

et al. 2015

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Cs exchanged heteropolyacid catalysts functionalized with various Sn contents were prepared by wet impregnation method. These catalysts were characterized by X-ray diffraction, FT-IR, Raman spectroscopy, temperature programmed desorption of ammonia and BET surface area measurements. The catalytic properties of SnCsPW catalysts were evaluated for the synthesis of glycerol carbonate and they exhibit an unprecedented activity for the higher glycerol conversion and selectivity towards glycerol carbonate under vacuum conditions. Sn-functionalized Cs exchanged heteropolyacid catalysts (CsPW) play a significant role in the enhancement of acidity, catalytic activity and stability. The glycerol conversion and the selectivity of carbonate formation mainly depend on the Sn content and acidity of the catalysts. Different reaction parameters such as Sn molar ratio, glycerol to urea molar ratio, reaction temperature were investigated and also optimum conditions were established. The catalyst containing molar ratio of 3:1 Sn-CsPW has shown highest conversion and glycerol carbonate selectivity.

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“…The resulting systems are characterized by different solubility and morphology in comparison to the parent heteropolyacid structures [32][33][34][35] [32,35,36]. Further, membranes composed of Cs 2.5 H 0.5 PW 12 O 40 and Nafion (relative to plane Nafion) exhibit superior stability against oxidative agents and better performance in PEMFCs [37][38][39].…”

Section: Introductionmentioning

confidence: 99%

Electrocatalytic properties of platinum nanocenters electrogenerated at ultra-trace levels within zeolitic phosphododecatungstate cesium salt matrices

Kolary-Zurowska

Zurowski

Dsoke

et al. 2014

J Solid State Electrochem

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A unique preparation method of obtaining stable composite film (with ultra-low platinum content) highly active towards oxygen reduction and hydrogen oxidation is presented here. The matrix for platinum centers consists of highsurface-area zeoli te-t ype aci dic salt of cesium phosphododecatungstate (Cs 2.5 H 0.5 PW 12 O 40 ) admixed with carbon (Vulcan XC-72) carriers. Platinum nanoparticles were deposited on the working electrode modified with matrix via corrosion of platinum counter electrode during cyclic voltammetry experiment conducted in acid electrolyte containing chloride ions. The results obtained from rotating disk voltammetry revealed that the composite film containing Pt nanoparticles at very low loadings (on the level of 2-5 μg cm −2 ) demonstrated remarkable electrocatalytic activity towards both oxygen reduction and hydrogen oxidation, particularly, when compared to the performance of the Cs 2.5 H 0.5 PW 12 O 40 -free system (i.e., containing only Vulcan support) prepared and examined under analogous conditions. The phenomenon should be primarily ascribed to the mesoporous nature of the matrix enabling immobilization and stabilization of small catalytic nanoparticles (1-2 nm diameters) inside the pores as well as to high surface acidity of the polyoxometalate-based salt providing proton-rich environment at the electrocatalytic interface.

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Preparation of bulk and supported heteropolyacid salts

Cited by 90 publications

References 14 publications

Phosphotungstic Acid Supported on a Nanopowdered ZrO₂ as a Filler in Nafion‐Based Membranes for Polymer Electrolyte Fuel Cells

Phosphotungstic Acid Supported on a Nanopowdered ZrO₂ as a Filler in Nafion‐Based Membranes for Polymer Electrolyte Fuel Cells

Synthesis and characterization of Cs-exchanged heteropolyacid catalysts functionalized with Sn for carbonolysis of glycerol to glycerol carbonate

Electrocatalytic properties of platinum nanocenters electrogenerated at ultra-trace levels within zeolitic phosphododecatungstate cesium salt matrices

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Preparation of bulk and supported heteropolyacid salts

Cited by 90 publications

References 14 publications

Phosphotungstic Acid Supported on a Nanopowdered ZrO2 as a Filler in Nafion‐Based Membranes for Polymer Electrolyte Fuel Cells

Phosphotungstic Acid Supported on a Nanopowdered ZrO2 as a Filler in Nafion‐Based Membranes for Polymer Electrolyte Fuel Cells

Synthesis and characterization of Cs-exchanged heteropolyacid catalysts functionalized with Sn for carbonolysis of glycerol to glycerol carbonate

Electrocatalytic properties of platinum nanocenters electrogenerated at ultra-trace levels within zeolitic phosphododecatungstate cesium salt matrices

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Phosphotungstic Acid Supported on a Nanopowdered ZrO₂ as a Filler in Nafion‐Based Membranes for Polymer Electrolyte Fuel Cells

Phosphotungstic Acid Supported on a Nanopowdered ZrO₂ as a Filler in Nafion‐Based Membranes for Polymer Electrolyte Fuel Cells