| In response to the current energy crisis,proton exchange membrane fuel cells?PEMFC?have gradually become a hot topic,and proton exchange membrane?PEM?is one of its core components.Metal organic framework?MOFs?show great development prospects in proton conduction due to their high specific surface area,adjustable pore size,thermal stability and chemical stability.The introduction of guest molecules in MOFs and complexing with polymers not only improve the electrical conductivity of MOFs,but also broadens the development of PEM.In this paper,the proton carrier heteropolyacid?PMoVx?,Br?nsted acid?BA=HCl,H2SO4,H3PO4,and CF3SO3H?and ionic liquid?ILs=DETA?Ac?3,TETA?Ac?4?pass the post-impregnation strategy compound to metal organic framework materials MIL-101and MOF-2.The obtained composite materials PMoVx@MIL-101,BA@MOF-2 and ILs@MOF-2 were doped with the polymers PVA/PVP and CS to prepare a series of compositemembranesPMoVx@MIL-101/PVA/PVP-X,BA@MOF-2/CS-Xand ILs@MOF-2/CS-X.The composites are monitored by several techniques like powder X-raydiffraction,scanningelectronmicroscopy,TGandNitrogen adsorption-desorption measurements to obtain the structural information of materials,and the proton conductivity and proton conduction mechanism were studied.The following is the specific research results.The proton conductivity of the above composites increases with increasing temperature and relative humidity,and protons in the composite membrane are conducted by the Grothuss mechanism.Particularly,?1?The best conductivity at 98%RH and 353 K is PMoV2@MIL-101-11.2(6.31×10-3S cm-1)and PMoV2@MIL-101/PVA/PVP-30%(1.96×10-33 S cm-1),the?value of which is about increased by 23 orders of magnitude than that for MIL-101(5.52×10-55 S cm-1)and PVA/PVP(2.11×10-6S cm-1)under identical conditions.?2?The best conductivity at98%RH and 338 K is CF3SO3H@MOF-2(3.47?10-33 S cm-1)and HCl@MOF-2/CS-10%(1.51?10-33 S cm-1),the?value of which is about increased by12 orders of magnitude than that for MOF-2(2.85×10-5S cm-1)and CS(4.64?10-4S cm-1)under identical conditions.At 23%RH and 338 K,H3PO4@MOF-2/CS-6%has the best conductivity(1.12?10-33 S cm-1),and compared to both MOF-2 and CS have improved.?3?DETA?AC?3@MOF-2 and DETA?AC?3@MOF-2/CS-4%reached the highest conductivity which is 1.86?10-33 S cm-11 and 6.13?10-33 S cm-11 at 98%RH and338 K respectively.The?value of which is about increased by 12 orders of magnitude than that for MOF-2 and CS under the same conditions. |
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