Proton‐conductive membranes based on vanadium substituted heteropoly acids with Keggin structure and polymers

Abstract

In this article, novel proton-conducting composite membranes SPEEK/PW 11 V and PVA/SiW 11 V were synthesized from vanadium substituted heteropoly acids (H 4 PW 11 VO 40 Á8H 2 O and H 5 SiW 11 VO 40 Á15H 2 O, abbreviated as PW 11 V and SiW 11 V) and polymers (SPEEK or PVA) at the weight ratio 70 : 30. The membranes were characterized by the infrared spectroscopy, X-ray powder diffraction, and scanning electron microscopy, which confirmed the maintenance of the Keggin framework and dispersion homogeneously in the polymer matrix without long-range ordering. Their proton-conducting properties were investigated with electrochemical impedance spectroscopy. The results show that the respective proton conductivities of SPEEK/PW 11 V and PVA/SiW 11 V membranes were in the order of 10 22 and 10 24 S cm 21 at ambient temperature. The temperature dependence of the two composite membrane electrolytes exhibit Arrhenius behavior, and the observed activation energies to be 15.82 kJ mol 21 for SPEEK/PW 11 V and 14.40 kJ mol 21 for PVA/SiW 11 V, which indicates that the proton conduction complies with the Grotthuss mechanism. V C 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42204.

Selectivity of Transport Processes in Ion-Exchange Membranes: Relationship with the Structure and Methods for Its Improvement

“…Moreover, such nanoparticles should not decrease the counterion transport along the pore walls, on the contrary, they will contribute to its increase due to an increase in the charge carrier concentration [ 67 , 205 ]. Heteropoly acids, their acid salts with alkali metal cations, or silica particles with heteropoly acids were shown to improve conductivity in such way [ 218 , 219 , 220 , 221 , 222 , 223 , 224 , 225 ]. On the other hand, the surface of such particles is hydrophilic, which contributes to an increase in water uptake.…”

SPEEK‐Tin dioxide proton conducting membranes: Effect of modifying agent of tin dioxide particles surface

“…[ 28–31 ] It was possible to detect the four absorption peaks of SO 3 H group in SPEEK: asymmetric and symmetric stretching of O=S=O (1,221 and 1,070 cm −1 ), S=O stretching at 1,018 cm −1 and S‐O stretching at 708 cm −1 . [ 30–32 ] The aromatic structure represented for C‐C was detected at 1,470 and 1,493 cm −1 upon due to the sulfonation process. [ 31 ] The band around 1,651 cm −1 was attributed to the carbonyl group.…”

“…[ 30–32 ] The aromatic structure represented for C‐C was detected at 1,470 and 1,493 cm −1 upon due to the sulfonation process. [ 31 ] The band around 1,651 cm −1 was attributed to the carbonyl group. [ 29,31 ]…”

“…However, the intensity of the band located around 1,470 cm −1 was less than observed for pristine SPEEK, suggesting the decrease of electron density of the substitute ring due to probable interaction between the hydroxyl group of the dioxide and the sulphonic group of SPEEK. [ 31 ]…”

Synthesis of Poly (Ether Ether) Ketone Sulfonated Membrane with Tin Dioxide Particles

“…The ability of the hybrid membranes to be less permeable to ethanol solution is associated with the change in the structure of the membranes, since the insertion of the oxide and acid particles reduces the available cross channels that the alcohol molecules pass. That is, they form a physical barrier which prevents the passage path of alcohol molecules [22]. Table 5 shows the proton conductivity values obtained for the two groups of membranes.…”