Hydrophilic and mesoporous SiO 2–TiO 2–SO 3H system for fuel cell membrane applications

Abstract

Hydrophilic and mesoporous sulfonated SiO 2–TiO 2–SO 3H systems as new additives for fuel cell electrolyte membranes are directly synthesized by the binary sol–gel reaction of TEOS–TiCl 4 and consecutive sulfonation with a hydrophilic generator, dihydroxy- m-benzenedisulfonic acid disodium salt. The sulfonation approach makes use of the simple chelating chemistry between the catecholic groups (dihydroxy benzene) and surface Ti ions of the inorganic ordered mesoporous SBA-15 structure. The system is successfully employed in fuel cell membrane applications with a composite Nafion membrane mixed with a mesoporous hydrophilic resin additive, and reveals an obvious enhancement of the proton conductivity at low humidity and elevated temperatures. This improvement was attributed to the excellent water retention capability of the hydrophilic mesoporous resin.