Functionalization and surface modification of TiO2 nanoparticles for proton exchange membrane fuel cell

Abstract

The fuel cell performance of sulfonated polyethersulfone (SPES) membrane was investigated with modified TiO2 nanoparticles. TiO2 nanoparticles were modified by sulfonation (STiO2) and surface modification with PANI (STiO2-PANI). The presence of the functional groups in the modified TiO2 was confirmed by Fourier transform infrared spectroscopy (FTIR) and XRD. The presence of sulfonic group in PES backbone was confirmed by 1HNMR spectroscopy. The SPES proton exchange membranes (PEM) were prepared by incorporating STiO2 and STiO2-PANI individually at 0.5% and 1% in the presence of N-methyl-2-pyrrolidone (NMP). The properties of the synthesized membrane were characterized by FTIR, XRD, Field Emission Scanning Electron Microscopy (FESEM). The performance of the membranes in terms of water uptake, swelling ratio, methanol uptake, ion exchange capacity were evaluated. Chemical stability, thermal properties and proton conductivity for the composite membranes were also determined. The highest proton conductivity is 1.07 × 10-3 S/cm exhibited by SPES/STiO2-PANI (0.5%) composite membrane. The ability of the membrane to hold more water molecules, presence of hydrophilic sulfonic acid groups and amine group of PANI were the main factors for the highest conductivity value. Surface modified STiO2 by PANI i.e., STiO2-PANI composite membrane exhibited excellent water uptake, ion exchange capacity, chemical and thermal properties with acceptable proton conductivity. The results represent that the composite membrane impregnated with STiO2-PANI to be a promising proton conducting material for fuel cell application.