Synthesis and electrochemical properties of substituted heteropoly acid with Dawson structure H7[In(H2O)P2W17O61]•23H2O

A new solid high-proton conductor, substituted heteropoly acid with Dawson structure H-7[In(H2O)P2W17O61]center dot 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(H2O)P2W17O61]center dot 23H(2)O is an excellent solid high-proton conductor with conductivity of 1.34 x 10(-3) S cm(-1) at 18 degrees 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.