Construction of well interconnected metal-organic framework structure for effectively promoting proton conductivity of proton exchange membrane
Construction of well interconnected metal-organic framework structure for effectively promoting proton conductivity of proton exchange membrane
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DOI：
10.1016/j.memsci.2017.03.031
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发表时间：
2017-07
影响因子：
9.5
通讯作者：
Zhuang Rao;K. Feng;Beibei Tang;Peiyi Wu
中科院分区：
文献类型：
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作者：
Zhuang Rao;K. Feng;Beibei Tang;Peiyi Wu
为了获得在高湿和无水条件下都具有高质子传导率的质子交换膜，将相互连接的UiO-66-NH 2连接到氧化石墨烯（GO）表面，然后掺入到Nafion基质中。由于GO表面的束缚效应和MOF颗粒之间的互连，构建了互连良好的金属有机框架（MOF）结构（GO@UiO-66-NH 2）。探讨了GO@UiO-66-NH 2在质子传导中的结构优势和机理。结果表明，适宜粒径的GO与UiO-66-NH 2之间的协同效应对促进质子转移尤为重要。GO上MOF的这种互连结构也使得Nafion的-SO 3 H和GO的-NH2@U1O-66-NH 2之间的酸/碱对途径更加连续。这有利于质子通过载体机制和Grotthuss机制传导。在90 °C、95%RH和无水条件下，复合膜的质子电导率分别达到0.303 S/cm和3.403×10−3S/cm，是改性Nafion膜的1.57倍和1.88倍（0.118 S/cm和1.182×10−3S/cm）。此外，复合膜显示出降低的甲醇渗透性，这归因于二维GO的阻挡效应和UiO-66-NH 2孔对甲醇的捕获。
To obtain proton exchange membrane (PEM) with high proton conductivities under both high humidity and anhydrous condition, interconnected UiO-66-NH2was tethered onto graphene oxide (GO) surfaces, and then incorporated into Nafion matrix. Thanks to tethering effect of GO surfaces and interconnection among MOF grains, well interconnected metal-organic framework (MOF) structures (GO@UiO-66-NH2) were constructed. The structural advantage and mechanism of GO@UiO-66-NH2in proton conduction were explored. It was found the synergistic effect between GO and UiO-66-NH2with suitable particle size was especially important for promoting proton transfer. Such interconnected structure of MOF on GO also made acid/base pair pathways between –SO3H of Nafion and –NH2of GO@UiO-66-NH2more consecutive. This was favorable to proton conduction via both vehicle mechanism and Grotthuss mechanism. The proton conductivity of the as-prepared composite membrane reached up to 0.303 S/cm under 90 °C, 95% RH, and 3.403×10−3S/cm under anhydrous condition, which was about 1.57 and 1.88 times higher than that of the recast Nafion (0.118 S/cm and 1.182×10−3S/cm), respectively. Furthermore, the composite membrane showed a reduced methanol permeability, which was attributed to the barrier effect of the two-dimensional GO and the trapping of methanol by UiO-66-NH2pores.