Metal-organic framework anchored sulfonated poly(ether sulfone) nanofibers as highly conductive channels for hybrid proton exchange membranes

In this study, a novel MOFs-anchored-nanofiber framework (UiO-66-NH2@NFs) is designed via electrospinning. To hybridize with Nafion matrix, UiO-66-NH2@NFs/Nafion membranes with acid-base pairs are fabricated. In the framework, sulfonated poly(ether sulfone) (SPES) nanofibers with effective -SO3H groups serve as bonding platforms and Uio-66-NH2 with -NH2 groups act as co-reinforcement units tethering in nanofibers. As systematically studied and compared in membrane performance, the homogeneous UiO-66-NH2@NFs/Nafion membrane with a moderate UiO-66-NH2 filler amount of 8 wt% present excellent performance on elevating proton conductivity of 0.27 S cm(-1) (80 degrees C, 100% RH) and inhibiting methanol permeability of 7.54 x 10(-7) cm(2) s(-1), respectively. The above superiorities can be attributed to the unique MOFs-anchored-nanofiber framework with balanced acid-base pairs. The interconnected UiO-66-NH2@NFs framework with hydrophilic SPES nanofibers and U10-66-NH2 offer consecutive proton transfer channels, making protons easily transfer via the hydration channels. Moreover, -NH2 groups in Ui0-66-NH2 and -SO3H groups in matrix interact via acid-base pairs, which synergistically conducts protons via proton hopping channels in the membranes. Meanwhile, the good compatibility of UiO-66-NH2@NFs with Nafion matrix resulting from the tight electrostatically interactions between -NH2 and -SO3H groups endow the hybrid membranes with suppressed methanol permeation and strengthened mechanical properties.