Sulfonated poly (ether ketone sulfone) composite membranes containing ZIF-67 coordinate graphene oxide showing high proton conductivity and improved physicochemical properties

Abstract

In this study, a sulfonated poly (ether ketone sulfone) with multiple sulfonic acid groups was prepared and named as MSP, where the multiple sulfonic acid groups in the polymer were located on its side chains of uneven length. And a series of hybrid membranes were prepared by introducing organic–inorganic fillers (ZIF-67/GO) into this side chain type polymer matrix. Among them, ZIF-67 was chemically grafted onto the GO sheet through coordination between Co+ and the carboxyl group of GO, bound to GO and grown uniformly. The ZIF-67/GO and hybrid membranes were characterized by FT-IR, XRD, SEM, AFM and 1H NMR. The hybrid membranes exhibited increasingly high proton conductivity from MSP (0.0876 S cm−1) to MSP-1 % ZIF-67/GO (0.1426 S cm−1) at 100 °C and 100 % relative humidity. Moreover, the hybrid membranes have excellent chemical stability. The results indicated that ZIF-67/GO was important for constructing of proton transport channels, and the prepared hybrid membranes showed great potential for application in PEM.