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The synthesis and characterization of an indium-substituted quaternary heteropoly acid with a Keggin structure, H4[In(H2O)PW9Mo2O39]·11H2O (PMo9W2In), is reported. At 18 °C under 80% relative humidity, PMo9W2In displays protonic conductivity of 2.32 × 10−4 S cm−1 with an activation energy of 35.52 kJ mol−1, indicating that it is a potential solid protonic conductor following the vehicle mechanism. Its conductivity increases with temperature in the measured temperature range. [ABSTRACT FROM AUTHOR]

A new vanadium and molybdenum-substituted quaternary silicon-containing heteropoly acid H6SiW9MoV2O40·15H2O has been synthesized in this paper by the stepwise acidification and the stepwise addition of elemental solutions. The structural feature and hydration of this product were characterized by IR, UV, XRD and TG-DTA, and its proton conductivity was measured by electrochemical impedance spectroscopy (EIS). The result of EIS shows that H6SiW9MoV2O40·15H2O is a solid high-proton conductor with a conductivity of 6.01 × 10−3 S cm−1 at 22 °C and 80% relative humidity, which increases at higher temperatures. Its conductive activation energy is 27.5 kJ mol−1, which suggests that the mechanism of proton conduction is dominated by the vehicle mechanism. [ABSTRACT FROM AUTHOR]

Two new high-proton conductors, indium-substituted ternary heteropoly acids with Keggin structures, H4[In(H2O)PW11O39]·11H2O and H5[In(H2O)SiW11O39]·8H2O, have been synthesized and characterized using elemental analysis, IR, UV, XRD and TG-DTA. Their proton conductivities were measured using electrochemical impedance spectroscopy (EIS), and the results indicate that H4[In(H2O)PW11O39]·11H2O and H5[In(H2O)SiW11O39]·8H2O are solid high-proton conductors with a conductivity of 2.60 × 10−4 S cm−1 and 5.25 × 10−4 S cm−1, respectively, at 18 °C and 80% relative humidity (RH). Their activation energies are 33.40 kJ mol−1 and 28.52 kJ mol−1, which suggests that the mechanism of proton conduction is the vehicle mechanism. In the range of the measured temperatures, the conductivity of both heteropoly acids increases with higher temperatures. [ABSTRACT FROM AUTHOR]

[Display omitted] • An excellent solid high-protonic conductor, H 5 PW 10 V 2 O 40 ·15H 2 O, is reported. • Its proton conductivity is 1.27 × 10−2 S·cm−1 at 18 °C, 80% relative humidity. • Its activation energy is 25.41 kJ·mol−1, following Vehicle mechanism. A typical high-protonic conductor, a kind of vanadium-substituted heteropoly acid, H 5 PW 10 V 2 O 40 ·15H 2 O, is synthesized with characterization and its proton conductive behavior also has been investigated. At 18 °C with 80% relative humidity, the protonic conductivity of H 5 PW 10 V 2 O 40 ·15H 2 O is 1.27 × 10−2 S·cm−1, an excellent protonic conductor. The proton conduction's activation energy is 25.41 kJ·mol−1, implying it following Vehicle mechanism. Higher temperature can accelerate the conductivity of H 5 PW 10 V 2 O 40 ·15H 2 O during the measured range. [ABSTRACT FROM AUTHOR]

To improve the proton conductive performance of heteropoly acids, a novel proton-conducting hybrid electrolyte SiW 9 MoV 2 /rGO/SPEEK was prepared by a simple and effective method based on sulfonated polyether ether ketone (SPEEK), H 6 SiW 9 MoV 2 O 40 (SiW 9 MoV 2 ) and reduced graphene oxide (rGO) in this work. This hybrid material was characterized by IR, TEM and XRD. Electrochemical impedance spectroscopy shows the obtained SiW 9 MoV 2 /rGO/SPEEK electrolyte exhibits an appreciable proton conductivity of 1.07 × 10 −2  S cm −1 at 16 °C and 70% relative humidity, which increases with higher temperature, and the activation energy for proton conduction of this hybrid film is 17.82 kJ mol −1 . The proton conduction is speculated to be the mixing of Grotthuss mechanism and Vehicle mechanism that accelerate the proton mobility in the hybrid electrolyte. This work lays a foundation in the field of HPAs-based separator films for proton exchange membrane devices and solid supercapacitors. [ABSTRACT FROM AUTHOR]

Tungstovanadosilicic heteropoly acid H 5 SiW 11 VO 40 ·15H 2 O has been successfully synthesized and characterized. The single crystal of this solid proton conductor was firstly obtained and the crystal structure was determined from single crystal X-ray diffraction. The complex crystallizes in the monoclinic system, space group C2/c, with a = 12.716(3) Å, b = 19.881(5) Å, c = 19.099(5) Å, α = 90°, β = 90.796°, γ = 90°, V = 4828(2) Å, Z = 4. Its proton conductivity was measured using electrochemical impedance spectroscopy (EIS) in the temperature range 15–55 °C, and the activation energy of the conductivity was determined. The results show that it has appreciable proton conductivity (7.93 × 10 −3 S cm −1 ) at 15 °C and 50% relative humidity, with an activation energy of 21.59 kJ mol −1 for proton conduction. The conductive mechanism is Vehicle mechanism. [ABSTRACT FROM AUTHOR]

The composite materials were prepared by 90 wt.% tungstovanadophosphoric heteropoly acids with Dawson structure (H7P2W17VO62·nH2O and H9P2W15V3O62·nH2O, abbreviated as P2W17V and P2W15V3), 5 wt.% silica gel (SiO2) and 5 wt.% organic polymers (polyvinylpyrrolidone, PVP or polyethylene glycol, PEG). The products were characterized by the infrared (IR), X-ray powder diffraction (XRD) and electrochemical impedance spectroscopy (EIS). EIS measurements show that the conductivity values PVP/P2W17V/SiO2, PVP/P2W15V3/SiO2 and PEG/P2W15V3/SiO2 are 1.89 × 10−2, 2.32 × 10−2 and 2.67 × 10−2 S cm−1 at 26 °C and 75% relative humidity, which increase with higher temperature. They exhibit low activation energies of 16.12, 16.85 and 14.02 kJ mol−1 for proton conduction, respectively. The mechanisms of proton conduction of the composite materials are also proposed. [ABSTRACT FROM AUTHOR]

A Dawson structure vanadium-substituted heteropoly acid, H 8 P 2 W 16 V 2 O 62 ·20H 2 O, has been synthesized and characterized by elemental analysis, IR, UV and XRD. Its proton conductivity was measured by the electrochemical impedance spectrum (EIS), and the result indicates that H 8 P 2 W 16 V 2 O 62 ·20H 2 O is a kind of solid high-proton conductor with conductivity of 1.89×10 −2 S cm −1 at 18 °C, and 80% relative humidity (RH). Its activation energy is 31.91 kJ mol −1 , suggesting that Vehicle mechanism of proton conduction. In the range of measured temperature, the conductivity of the heteropoly acid increases with higher temperature. [ABSTRACT FROM AUTHOR]

A new vanadium and molybdenum-substituted Keggin-type quaternary heteropoly acid H 5 PW 9 MoV 2 O 40 ·10H 2 O has been synthesized by the stepwise acidification and the stepwise addition of element solutions. The product is characterized by the IR, UV, XRD, TG–DTA and electrochemical impedance spectroscopy (EIS). EIS measurement shows the conductivity value of H 5 PW 9 MoV 2 O 40 ·10H 2 O is 8.92×10 −3 S cm −1 at 22 °C and 80% relative humidity, which increases with higher temperature. Its mechanism of proton conduction is Vehicle mechanism for its conductive activation energy of 23.45 kJ mol −1 . [ABSTRACT FROM AUTHOR]

Various photocatalysts composed of undecatungstotitanotitanic heteropoly acid (H 4 [Ti(H 2 O)TiW 11 O 39 ]·7H 2 O) loaded on silica (TiW 11 Ti/SiO 2) were prepared by sol-gel method. The TiW 11 Ti/SiO 2 hybrid materials were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and Diffuse reflectance spectra (DRS). The photocatalytic performance was investigated by photocatalytic degradation of brilliant dye X-3B under ultraviolet light irradiation. The TiW 11 Ti/SiO 2 hybrid showed higher photocatalytic activity than pure TiW 11 Ti and TiW 11 Ti + SiO 2 (TiW 11 Ti mixed simply with SiO 2). Among three different loading weights of TiW 11 Ti for the hybrids, the degradation efficiencies of dye X-3B displayed the following order: 45 wt% > 30 wt% > 60 wt%. Unlabelled Image • H 4 [Ti(H 2 O)TiW 11 O 39 ]·7H 2 O loaded on silica were prepared by sol-gel method. • The photocatalytic property of TiW 11 Ti/SiO 2 was studied by degradation of X-3B. • The TiW 11 Ti loading weights of 45 wt% displayed the best degradation performance. [ABSTRACT FROM AUTHOR]

The material (TOAMe)5[SiW11VO40] was synthesized from a heteropoly acid and a simple quaternary ammonium ionic liquid as a new organic-inorganic hybrid material. It has a phase transition and ion conductivity of ∼2.03×10–3 Ω–1 cm–1 at 26°C. [ABSTRACT FROM AUTHOR]

Abstract: Tungstovanadophosphoric heteropoly acid H4PW11VO40·8H2O with Keggin structure has been synthesized by the stepwise acidification and the stepwise addition of element solutions. The optimal proportion of component compounds and pH value in the synthesis reaction were given. The crystal structure was determined from single crystal X-ray diffraction. The complex crystallises in the space group I-4, with a =18.7648(9)Å, b =18.7648(9)Å, c =14.5762(9)Å, α =90°, β =90°, γ =90°, V =5132.5(6)Å, Z =2. The product possesses Keggin structure and its conductivity was 1.50×10−2 Scm−1 at 26°C and 75% relative humidity by electrochemical impedance spectroscopy (EIS) measurement, with an activation energy of 25.66kJmol−1 for proton conduction. The mechanism of proton conduction for this compound is vehicle mechanism. [Copyright &y& Elsevier]