A new HPAs H20[P8W60Ta12(H2O)4(OH)8O236]125H2O (H-1) which comprises a Ta/W mixed addenda heteropolyanion, 20 protons, and 125 crystalline water molecules has been prepared through ion-exchange method. The structure and properties of H-1 have been explored in detail. AC impedance measurements indicate that H-1 is a good solid state proton conducting material at room temperature with a conductivity value of 7.2 10 3 S cm-1 (25 °C, 30% RH). Cyclic voltammograms of H-1 indicate the electrocatalytic activity towards the reduction of nitrite. Hammett acidity constant H0 of H-1 in CH3CN is -2.91, which is the strongest among the present known HPAs. Relatively, H-1 exhibits excellent catalytic activities toward acetal reaction.

Shujun Li, Qingpo Peng, Xuenian Chen*, Ruoya Wang, Jianxin Zhai, Weihua Hu , Fengji Ma*, Jie Zhang*, Shuxia Liu. A Ta/W Mixed Addenda Heteropolyacid with Excellent Acid Catalytic Activity and Proton‐Conducting Property[J]. Journal of Solid State Chemistry, 2016, 243(48):1-7.
http://www.sciencedirect.com/science/article/pii/S0022459616303024