Preparation of Sulfonated Polysulfone/sulfonated Titanium Dioxide Hybrid Membranes for DMFC Applications

ABSTRACTSulfonated titanium dioxide (STiO2) was prepared by the reaction of TiO2 with 1,3‐propanesultone. Novel STiO2 incorporated sulfonated poly(aryl ether sulfone) (SPAES) nanocomposite proton exchange membranes (PEMs) were made by solution casting. Fourier transform infrared, X‐ray photoelectron spectroscopy, and proton nuclear magnetic resonance indicated the successful preparation of STiO2 and SPAES. The thermogravimetric analysis and oxidative stability testing results implied that SPAES/STiO2 membranes had better stability than pristine SPAES membrane. Meanwhile, the scanning electron microscopy spectra exhibited that the introduction of sulfonated groups on the surface of TiO2 significantly improved its dispersibility in SPAES matrix. More specifically, SPAES membrane incorporated with 2%STiO2 exhibited higher proton conductivity (60 mS cm−1), lower methanol permeability (2.1 × 10−7 cm2 s−1) and better proton selectivity (28.0 × 104 S s cm−3) than that of pure SPAES and SPAES/1%TiO2 membrane. The SPAES‐1%STiO2 membrane showed better performance in direct methanol fuel cell (DMFC) test than SPAES and Nafion 117 due to the reduction of methanol crossover. From these results, it is evident that SPAES/STiO2 nanocomposite PEMs have great potential for applications in DMFCs. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48938.