Synthesis and performance of high-proton conductor undecatungstochromoindic heteropoly acid

The undecatungstochromoindic heteropoly acid (HPA) H6[In(H2O)CrW11O39]·11H2O was synthesized for the first time by the stepwise acidification and the stepwise addition of solutions of the component elements, as well as the ion exchanging cooling method. The optimal proportion of the component compounds and the pH of the synthesis reaction are given. The product was characterized by means of inductively coupled plasma (ICP), IR, UV, X-ray diffraction (XRD) and thermal analysis. The IR, UV and XRD indicate that H6[In(H2O)CrW11O39]·11H2O possesses the Keggin structure. The results of AC impedance measurement show that its proton conductivity is 1.15×10−3 S cm−1 at room temperature (16 °C).