Topic
Phosphotungstic acid
About: Phosphotungstic acid is a research topic. Over the lifetime, 1925 publications have been published within this topic receiving 38059 citations. The topic is also known as: Phosphowolframic acid.
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TL;DR: In this article, a series of phosphotungstic acid (HPW)/TiO2 materials with three-dimensional continuous and ordered macroporous structure are synthesized by colloidal crystal templates and used as catalysts for oxidative desulfurization (ODS) of model oil.
46 citations
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TL;DR: In this paper, Cs-exchanged phosphotungstic acids (Cs x H 3− x PW 12 O 40, x ǫ = 1 − 3) were examined as a catalyst for the hydrocracking of extra-heavy oil (vacuum residue, API gravity = 2.3°).
46 citations
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TL;DR: 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) as mentioned in this paper.
Abstract: 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.
46 citations
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TL;DR: In this paper, a new amino-functionalized bipyridine-heteropolyacid ionic hybrid was prepared by protonating and anion-exchanging the amino-attached bipyridine ionic liquid with phosphotungstic acid, and characterized by FT-IR, 1 H NMR, UV-vis, XRD, SEM, TG, surface area, melting point, and elemental analysis.
Abstract: A new amino-functionalized bipyridine–heteropolyacid ionic hybrid was prepared by protonating and anion-exchanging the amino-attached bipyridine ionic liquid with phosphotungstic acid, and characterized by FT-IR, 1 H NMR, UV–vis, XRD, SEM, TG, BET surface area, melting point, and elemental analysis. Its catalytic activity was evaluated in the oxidation of benzyl alcohol with aqueous H 2 O 2 . The hybrid catalyst is proved to be a highly efficient solid catalyst for solvent-free oxidation of benzyl alcohol with H 2 O 2 , which is featured by the fast reaction rate, high conversion and selectivity, easy recovery, and quite steady reuse.
46 citations
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TL;DR: A series of SPEEK/HPW/Ppy-n composite membranes with a sandwich structure were successfully prepared by surface modification with polypyrrole (Ppy) in order to stabilize phosphotungstic acid (HPW) in poly(ether ether ketone)s (SPEEKs) and reduce the methanol crossover.
Abstract: A series of SPEEK/HPW/Ppy-n composite membranes with a sandwich structure were successfully prepared by surface modification with polypyrrole (Ppy) in order to stabilize phosphotungstic acid (HPW) in poly(ether ether ketone)s (SPEEKs) and reduce the methanol crossover. Ppy coatings with a large number of secondary ammonium groups (NH2+) interact with anions of HPW to decrease HPW leaching from the membrane. In addition, the hydrophobic Ppy layers allow for little methanol transport, which leads to a significant decline in methanol crossover with reasonable levels of proton conductivity. The properties of the membranes were investigated in detail by UV, SEM, ac impedance, and TGA. As observed, Ppy-modified membranes were better at immobilizing HPW and exhibited higher selectivities than previously reported SPEEK/HPW composite membranes. All the results indicate that the SPEEK/HPW/Ppy-n composite membranes are excellent candidates for direct methanol fuel cells.
46 citations