فهرست نشریات علمی دسترسی آزاد ایران

The development of high-performance proton exchange membranes (PEMs) is crucial for improving the efficiency and durability of fuel cells. In this study, sulfonated polystyrene (SPS) was reinforced with different loadings of MIL-101(Cr) (2.5, 5, and 7.5 wt%), a highly porous metal–organic framework (MOF) with a specific surface area of 1,811.06 m² g⁻¹, to fabricate nanocomposite membranes via a solution-casting method. The incorporation of MIL-101(Cr) significantly enhanced key physicochemical and electrochemical properties of the membranes. Water uptake increased from 38.2% to 48.6%, while the ion exchange capacity (IEC) reached up to 0.95 meq g⁻¹ with increasing MOF content. The composite membranes exhibited excellent oxidative stability, retaining more than 97% of their original weight after exposure to Fenton’s reagent at 80 °C. Electrochemical impedance spectroscopy (EIS) revealed that proton conductivity increased with MIL-101(Cr) loading, reaching a maximum value of 0.0914 S cm⁻¹ at 80 °C and 60% relative humidity for the membrane containing 7.5 wt% MIL-101(Cr). In addition, methanol permeability remained in the order of 10⁻⁷ cm² s⁻¹, leading to a markedly improved selectivity factor compared to the MOF-free membrane. These results demonstrate that MIL-101(Cr)-based SPS nanocomposite membranes exhibit a well-balanced combination of high proton conductivity, low methanol crossover, and excellent oxidative stability, highlighting their strong potential for application in next-generation proton exchange membrane fuel cells (PEMFCs) and direct methanol fuel cells (DMFCs).