Preparation And Conductive Performance Of Phosphorus-containing Ternary Heteropolv Compounds And Their Hybrid Materials

Two kinds of substituted heteropoly acids with Keggin structure H4PW11VO40·8H2O (PW11V) and H6PW9V3O40·14H2O (PW9V3), have been synthesized by the stepwise acidification-stepwise addition of element solutions-ether extraction. Their single crystals were obtained and the crystal structures were determined from single crystal X-ray diffraction. The data of crystal structure are following:for H4PW11VO40·8H20, in the space group I-4, with a=18.7648(9) A, b=18.7648(9) A,c=14.5762(9)A,a=90°,β=90°, γ=90°, V=5132.5(6) A, Z=2.For H6PW9V3O40·14H2O, in the space group R-3m, with a=16.4374(9) A, b=16.4374(9) A,c=25.3866(14)A,a=90°,β=90°,γ=120°, V=5940.20A, Z=6. H7P2W17VO62·28H2O with Dawson structure was also synthesized by this method. In addition, a general strategy in terms of the degradation-ion exchange-freezing method was used to design H9P2W15V3O62·28H2O with Dawson structure. The products were characterized by chemical analysis, potentiometric titration, IR, UV,31P NMR, XRD and TG-DTA. The proton conductivities of the products were measured at different temperatures and75%relative humidity (RH) by electrochemical impedance measurement. According to the experimental results, their condutivities are up to10-2S·cm-1. In the range of measured temperature, their conductivities increase with higher temperature. The conductivities of heteropoly acids with Dawson structure are obviously higher than that of heteropoly acids with Keggin structure. Their activation energies of proton conduction are25.66(PW11V),25.68(PW9V3),32.23(P2W17V) and31.35(P2W15V3) kJ·mol-1, respectively. Their mechanisms of proton conduction are Vehicle mechanism.Some hybrid materials were prepared from as-synthesized heteropoly acids, organic polymers (polyvinylpyrrolidone, PVP or polyethylene glycol, PEG) and tetraethyl orthosilicate (TEOS):PVP/PW11V, PEG/PW11V, PVP/PW9V3, PEG/PW9V3(80wt.%HPA with Keggin structure and20wt.%organic polymer);PVP/P2W17V, PEG/P2W17V, PVP/P2W15V3, PEG/P2W15V3(90wt.%HPA with Dawson structure and10wt.%organic polymer); PVP/PW11V/SiO2, PEG/PW11V/SiO2, PVP/PW9V3/Si02, PEG/PW9V3/Si02(80wt.%HPA with Keggin structure,20wt.%organic polymer and10wt.%SiO2); PVP/P2W17V/Si02, PEG/P2W17V/Si02, PVP/P2W15V3/SiO2and PEG/P2W15V3/Si02(90wt.%Dawson,5wt.%organic polymer and5wt.%SiO2).The hybrid materials were characterized by IR and XRD. The results show that structures of heteropoly anions in the hybrid materials are still remained and the products are considered amorphous.The proton conductivities of hybrid materials were measured by electrochemical impedance measurement. According to the proton conductivities at different temperatures, their activation energies of proton conduction are obtained and smaller than the corresponding heteropoly acids.Their mechanisms of proton conduction are Grotthuss mechanism.A serious of ionic liquid-based heteropoly compounds,[MIMPS]4PW11VO40,[PyPS]4PW11VO40,[MIMPS]6PW9V3O40,[PyPS]6PW9V3O40,[MIMPS]7P2W17VO62,[PyPS]7P2W17VO62,[MIMPS]9P2W15V3O62,[PyPS]9P2W,5V3O62,[PyPS]4PMo11VO40,[PyPS]H6P2W17VO62and [PyPS]H8P2W15V3O62, have been synthesized from as-synthesized heteropoly acids and1-(3-sulfonic group) propy1-3-methyl imidazolium (MIMPS) and1-(3-sulfonic group) propyl-pyridine (PyPS).These products were characterized by IR, UV, XRD and TG-DTA. In the IR spectra, their M-Od antisymmetry streching vibrational frequencies are red-shift compared with that of the corresponding heteropoly acids. The results from differential thermal analysis show that the thermal stabilities of these compounds are lower than that of pristine heteropoly acids.The conductivities of the products were also obtained.