Porous laminar membranes hold great promise to realize ultrafast ion transfer if efficient and stable transfer channels are constructed in vertical direction.Here,metal-organic framework(MOF)nanosheets bearing imidazo...Porous laminar membranes hold great promise to realize ultrafast ion transfer if efficient and stable transfer channels are constructed in vertical direction.Here,metal-organic framework(MOF)nanosheets bearing imidazole molecules in the pores were designed as building blocks to assemble free-standing MOF laminar membrane.Then,Nafion chains were threaded into the pores induced by electrostatic attraction from imidazole molecules by slowly filtering dilute Nafion solution.We demonstrate that the threaded Nafion chains lock adjacent MOF nanosheets,affording highly enhanced structural stability to the resultant laminar membrane with almost no water swelling.Significantly,abundant acid-base pairs are formed in the pores along Nafion chains,working as efficient,continuous conduction pathways in vertical direction.Proton conductivities as high as 110 and 46 mS·cm^(-1)are obtained by this membrane under 100%and 40%relative humidity(RH),respectively,which are two orders of magnitude higher than that of pristine MOF membrane.The conductivity under low humidity(40%RH)is even over 2 times higher than that of commercial Nafion membrane,generating the maximum power density of 1,100 mW·cm^(-2)in hydrogen fuel cell(vs.291 mW·cm^(-2)of Nafion membrane).Besides,the influence of water state on proton transfer in confined space is investigated in detail.展开更多
基金The authors would like to acknowledge the financial support from the National Natural Science Foundation of China(No.U2004199)Excellent Youth Foundation of Henan Province(No.202300410373)+3 种基金China Postdoctoral Science Foundation(Nos.2021T140615 and 2020M672281)Natural Science Foundation of Henan Province(No.212300410285)Young Talent Support Project of Henan Province(No.2021HYTP028)Center for advanced analysis and computational science,Zhengzhou University is also highly acknowledged.
文摘Porous laminar membranes hold great promise to realize ultrafast ion transfer if efficient and stable transfer channels are constructed in vertical direction.Here,metal-organic framework(MOF)nanosheets bearing imidazole molecules in the pores were designed as building blocks to assemble free-standing MOF laminar membrane.Then,Nafion chains were threaded into the pores induced by electrostatic attraction from imidazole molecules by slowly filtering dilute Nafion solution.We demonstrate that the threaded Nafion chains lock adjacent MOF nanosheets,affording highly enhanced structural stability to the resultant laminar membrane with almost no water swelling.Significantly,abundant acid-base pairs are formed in the pores along Nafion chains,working as efficient,continuous conduction pathways in vertical direction.Proton conductivities as high as 110 and 46 mS·cm^(-1)are obtained by this membrane under 100%and 40%relative humidity(RH),respectively,which are two orders of magnitude higher than that of pristine MOF membrane.The conductivity under low humidity(40%RH)is even over 2 times higher than that of commercial Nafion membrane,generating the maximum power density of 1,100 mW·cm^(-2)in hydrogen fuel cell(vs.291 mW·cm^(-2)of Nafion membrane).Besides,the influence of water state on proton transfer in confined space is investigated in detail.
