Synergistic effect of graphene oxide and carbon nanotubes on sulfonated poly(arylene ether nitrile)-based proton conducting membranes

Abstract

A strategy to prepare graphene oxide (GO)/carbon nano-tubes (CNTs)/sulfonated poly(arylene ether nitrile) (SPEN) composite membranes aimed for the proton exchange membrane is presented herein. GO and CNTs were incorporated into SPEN to improve the performances of proton exchange membrane. To study the synergistic effect of GO and CNTs, GO/SPEN and CNTs/SPEN membranes were also fabricated. The influences of GO and CNTs upon the microstructures, including thermal and mechanical properties, water uptake, swelling, proton conductivity and methanol permeability of composite membranes were investigated in detail. The membranes combining GO and CNTs could effectively avoid the self-agglomeration of GO or CNTs. In such a way, efficient proton transport channels were constructed by homogeneous dispersion of GO and CNTs within SPEN, leading to enhancement of proton conductivity. The proton conductivity of GO/CNTs/SPEN composite membrane with the ratio of 2:2 achieved the highest value of 0.1197 S/cm at 20 °C. Meanwhile, low methanol permeability (2.015 × 10−7 cm2 s−1) was still maintained. Consequently, the combination of CNTs and GO exhibited a favorable synergistic effect on the selectivity of proton exchange membrane, which is better than pure SPEN, Nafion 117, GO/SPEN, and CNTs/SPEN membranes. This feasibility study could provide an alternative approach to design GO/CNTs-based proton-conducting membranes for DMFC applications.