Highly Proton-conducting Hybrid Materials containing Keggintype Tungstovanadophosphoric Acids and Organic Polymers

Four new proton-conducting hybrid materials were prepared by Keggin-type tungstovanadophosphoric heteropoly acids H4PWiiVO.ioJiI H2O (PW11V) and H6PW^VsOu-nftO (PW9V3), organic polymers (polyvinylpyrrolidone, PVP or polyethylene glycol, PEG) and silica gel (SiO2) at weight ratio of 80:10:10. Structural analysis reveals that the Keggin anions maintained in the hybrid materials, and these products exhibit high proton conductivity with 1.36×1.36 ×10-3 (PVP/PWiiV/SiO2), 3.44×10-3 (PEG/PW11V/SiO2), 8.90x10-3 (PVP/PW9V3/SiO2) and 1.63×10-2 S-cm-1 (PEG/PW9V3/SiO2) at 26 °C and 75% relative humidity, increasing with higher temperature. Their activation energy of proton conduction is 17.96, 15.34, 17.54, 14.23 kJ^mol-1, respectively, which is lower than the corresponding pure acid. The proton conduction mechanisms of these materials are also proposed.