Highly proton-conducting hybrid materials ( P2W17V /PEG and P2W17V/PEG/SiO2 ) were prepared by heptadecatungstovanadodiphosphoric heteropoly acid with Dawson structure ( P2W17V , 90 wt.%), polyethylene glycol (PEG, 10 wt.% and 5 wt.%) and silica gel ( SiO2 , 0 wt.% and 5 wt.%). The products were characterized by the infrared (IR) spectrum, X-ray powder diffraction (XRD) analysis and electrochemical impedance spectrum (EIS). The result reveals that their conductivity values are 1.02 × 10-2 and 2.58 × 10-2S ⋅ cm-1 at room temperature (26°C) and 75% relative humidity (RH), respectively. Their conductivities increase with higher temperature and these activation energies of proton conduction are 9.51 and 14.95 kJ⋅mol-1, which are lower than that of pure heteropoly acid (32.23 kJ⋅mol-1). These mechanisms of proton conduction for these two materials are Grotthuss mechanism.
Synthesis and conductivity of substituted heteropoly acid with Dawson structure H7[Ga(H2O)P2W17O61]·18H2O
