Synthesis and conductive performance of quaternary molybdotungstovanadophosphoric heteropoly acid with Keggin structure

Abstract 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 .