Pentadecatungstotrivanadodiphosphoric heteropoly acid with Dawson structure: Synthesis, conductivity and conductive mechanism.

A general strategy in terms of degradating and ion-exchange synthesis was used to design pentadecatungstotrivanadodiphosphoric heteropoly acid H(9)P(2)W(15)V(3)O(62)·28H(2)O with Dawson structure and excellent conductivity. The product was characterized by ICP-MS, IR, UV, XRD, (31)P NMR, TG-DTA and electrochemical impedance spectroscopy (EIS). The results indicate that H(9)P(2)W(15)V(3)O(62)·28H(2)O possesses the Dawson structure. EIS measurements show a high conductivity (3.64 × 10(-2) S cm(-1) at 26 °C and 75% relative humidity), with an activation energy of 31.34 kJ mol(-1) for proton conduction. Its mechanism for proton conduction is the Vehicle mechanism.