Proton conductivity of naphthalene sulfonate formaldehyde resin-doped mesoporous niobium and tantalum oxide composites

Turley, Jonathan P. and Romer, Frederik and Trudeau, Michel L. and Dias, Marcos L. and Smith, Mark E. and Hanna, John V. and Antonelli, David M. (2015) Proton conductivity of naphthalene sulfonate formaldehyde resin-doped mesoporous niobium and tantalum oxide composites. ChemSusChem, 8 (2). pp. 301-309. ISSN 1864-5631

Abstract

Proton conductivity in a series of mesoporous niobium and tantalum metal oxide (mX2O5) composites of naphthalene sulfonic acid formaldehyde resin (NSF) that are resistant to moisture loss at temperatures greater than 50 °C is reported. The investigation focuses on the effect to proton conductivity by changing pore size and metal in the mesostructure of the mX2O5 system and thus, a series of mX2O5-NSF composites were synthesized with C6, C12, and C18 templates. These were characterized by XRD, thermogravimetric analysis, nitrogen adsorption, and scanning TEM and then studied using impedance spectroscopy to establish proton conductivity values at various temperatures ranging from 25 to 150 °C. The most promising sample displayed a conductivity of 21.96 mS cm−1 at 100 °C, surpassing the literature value for Nafion 117 (ca. 8 mS cm−1). 1H and 13C solid state NMR studies the mX2O5-NSF composites demonstrate that the oligomeric nature of the NSF is preserved while in contact with the mX2O5 surface, thus facilitating conductivity.