Wenfu Yan

Synthesis and electrochemical properties of substituted heteropoly acid with Dawson structure H-7[In(H2O)P2W17O61]center dot 23H(2)O

A new solid high-proton conductor, substituted heteropoly acid with Dawson structure H(7)[In(H(2)O)P(2)W(17)O(61)]·23H(2)O, has been synthesized by the degradation/ion exchange/freezing method. The pH of the synthesis reaction was given. The product was characterized by chemical analysis, IR, UV, XRD and TG-DTA. The determination of conductivity shows that H(7)[In(H(2)O)P(2)W(17)O(61)]·23H(2)O is an excellent solid high-proton conductor with conductivity of 1.34 × 10(-3) S cm(-1) at 18 °C, and 70% relative humidity (RH). Its activation energy is 37.72 kJ mol(-1), which suggests that its mechanism of proton conduction is the Vehicle mechanism.

Synthesis and conduction mechanism of high proton conductor H6SiW10V2O40⋅14H2O

A ternary heteropoly acid (HPA) H6SiW10V2O40⋅14H2O was prepared and investigated in this paper. The structure feature and hydration of this HPA was characterized by IR, XRD, UV, and TG-DTA. This HPA exhibits a high proton conductivity, which is 7.4×10−3S⋅cm−1 at 25∘C and 70% relative humidity. It is a novel high proton conductor. The conductivity increases with higher temperature, and it exhibits Arrhenius behavior, with the activation energy value of 21.02kJ⋅ mol−1 for proton conduction, indicating the proton conduction mechanism is dominated by vehicle mechanism.

Solid high-proton conductor tungstovanadozincic acid with transition metal as central atom: Synthesis and conductivity

A Keggin-type vanadium-substituted tungstovanadozincic heteropoly acid H7ZnW11VO40 ⋅ 8H2O, with the transition metal as central atom, was firstly synthesized and characterized. Its proton conductivity was measured by the electrochemical impedance spectrum (EIS), and the result indicates that the H7ZnW11VO40 ⋅ 8H2O is a solid high-proton conductor with conductivity of 3.26 × 10-3S ⋅ cm-1 at 58°C, 50% relative humidity. Its activation energy is 29.50 kJ ⋅ mol-1, which suggests that the mechanism of proton conduction is the Vehicle mechanism.

Syntheses and electrochemical properties of polyoxometalate salts with Dawson structure

Two new solid hybrid molecular materials [PyPS]H6P2W17VO62 and [PyPS]H8P2W15V3O62 have been synthesized from 1-(3-sulfonic group) propyl-pyridine ionic liquid cation and tungstovanadophosphoric anion with the Dawson structure. They were characterized by element analysis, impedance spectroscopy (IS), IR- and UV-spectroscopy. The formation of the hybrid molecular compounds with the Dawson structure was showed. Ion conductivity of [PyPS]H6P2W17VO62 and [PyPS]H8P2W15V3O62 are 3.99 × 10−3 and 7.37 × 10−3 S cm−1 at 18°C and 55% relative humidity respectively. The activation energies of proton conductivity are 28.2 and 26.7 kJ mol−1 respectively.

Reversible phase transformation-type layer shape electrolyte based on POM and quaternary ammonium salt

A novel kind of organic–inorganic layer shape material, polyoxymetalates (POM)-type ionic liquid (IL) with Keggin structure and simple quaternary ammonium salt, (TOAMe)4PW11VO40 (trioctylmethylammonium = TOAMe,…) is synthesized and characterized by IR, UV, X-ray diffraction (XRD), TG–DTA. Its electrochemical property was investigated by cyclic voltammgram. Research results released the vanadium and the POM structure in the compound can process reduction in DMSO, which is unlikely in water solution as a simple hydrated ion because water will protonize substrate.