Preparation and properties of sulfonated lavoisier framework(MIL-101(Cr)-SO₃H)/sulfonated polyarylethersulfone with cardo hybrid proton exchange membranes

The material of institute lavoisier framework (MIL-101(Cr)) was synthesized through hydrothermal synthesis. Then sulfonic groups (SO₃H) were introduced into cages of MIL-101(Cr) by post sulfonation reaction to obtain MIL-101(Cr)-SO₃H with proton conduction property. FTIR results confirm the successful introduction of sulfonic groups to MIL-101(Cr). SEM and XRD results indicate that the particle size of MIL-101(Cr) and MIL-101(Cr)-SO₃H are in the range of nanometer scale, and no crystal structural collapse can be observed for as-prepared MIL-101(Cr)-SO₃H. The elemental analysis shows that the sulfonation degree of MIL-101(Cr)-SO₃H is 0.36. Then MIL-101(Cr)-SO₃H is embedded into sulfonated polyarylethersulfone with cardo (SPES-C) to obtain a series of MIL-101(Cr)-SO₃H/SPES-C hybrid proton exchange membranes for fuel cell application. SEM characterization demonstrates that MIL-101(Cr)-SO₃H is uniformly dispersed in the MIL-101(Cr)-SO₃H/SPES-C hybrid membrane. SPES-C and MIL-101(Cr)-SO₃H show good compatibility and no interfacial defects appear in the MIL-101(Cr)-SO₃H/SPES-C hybrid membranes. TGA analysis results show that the thermal stability of MIL-101(Cr)-SO₃H/SPES-C hybrid membranes is excellent. The introduction of MIL-101(Cr)-SO₃H enhances the water uptake of MIL-101(Cr)-SO₃H/SPES-C hybrid membranes and reduces the methanol permeability. The proton conductivity of MIL-101(Cr)-SO₃H/SPES-C hybrid membranes increases with increasing MIL-101(Cr)-SO₃H mass fraction and testing temperature. When mass fraction of MIL-101(Cr)-SO₃H is 5wt%, the proton conductivity of MIL-101(Cr)-SO₃H/SPES-C hybrid membrane reaches to 0.162 S·cm^-1 at 80℃, which is 20.1% higher than that of the commercial Nafion membrane (0.134 S·cm^-1).