Deconstructing proton transport through atomically thin monolayer CVD graphene membranes
Deconstructing proton transport through atomically thin monolayer CVD graphene membranes
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DOI：
10.1039/d2ta01737g
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发表时间：
2022-04-20
影响因子：
11.9
通讯作者：
Kidambi, Piran R.
中科院分区：
文献类型：
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作者：
Chaturvedi, Pavan;Moehring, Nicole K.;Kidambi, Piran R.
通过石墨烯和其他2D材料的原子薄晶格的选择性质子（H+）渗透为能量转换/存储和新型分离提供了新的机会。实际应用需要通过化学气相沉积（CVD）等方法进行可扩展的合成，这些方法不可避免地会引入亚纳米缺陷，晶界和皱纹，并且了解它们对H+传输和大面积膜的选择性的影响是必要的，但仍然难以捉摸。使用电驱动的H+和钾离子（K+）的传输，我们探测的影响，在单层CVD石墨烯的内在亚纳米缺陷跨越长度尺度的第一次。在微米尺度下，CVD石墨烯的面积H+电导率（类似于4.5-6 mS cm（-2））与机械剥离的石墨烯的面积H+电导率相当，表明在域内类似的高结晶质量，尽管具有K+传输（类似于1.7 mS cm（-2））。然而，厘米级的Nafion|石墨烯|具有几个石墨烯域的Nafion器件显示出类似于339 mS cm（-2）的面积H+电导和类似于23.8 mS cm（-2）的K+电导（H+的石墨烯电导类似于1735 mS cm（-2），K+的石墨烯电导类似于47.6 mS cm（-2））。使用一个超导传输模型和Nafion填充的聚碳酸酯轨道蚀刻支持，我们系统地解构了厘米级CVD石墨烯的H+电导增加的数量级。通过界面聚合减轻缺陷（>1.6 nm）、褶皱和撕裂导致通过CVD石墨烯中的固有亚纳米质子选择性缺陷，对于H+的电导率类似于1848 mS cm（-2），对于K+的电导率类似于75.3 mS cm（-2）（H+/K+选择性类似于24.5）。我们展示了原子级薄膜具有比最先进的质子交换膜更高的离子选择性，同时保持可比的H+电导。我们的工作提供了一个新的框架，以评估H+的电导率和选择性的大面积二维膜，并突出了内在的亚纳米质子选择性缺陷的实际应用中的作用。
Selective proton (H+) permeation through the atomically thin lattice of graphene and other 2D materials offers new opportunities for energy conversion/storage and novel separations. Practical applications necessitate scalable synthesis via approaches such as chemical vapor deposition (CVD) that inevitably introduce sub-nanometer defects, grain boundaries and wrinkles, and understanding their influence on H+ transport and selectivity for large-area membranes is imperative but remains elusive. Using electrically driven transport of H+ and potassium ions (K+) we probe the influence of intrinsic sub-nanometer defects in monolayer CVD graphene across length-scales for the first time. At the micron scale, the areal H+ conductance of CVD graphene (similar to 4.5-6 mS cm(-2)) is comparable to that of mechanically exfoliated graphene indicating similarly high crystalline quality within a domain, albeit with K+ transport (similar to 1.7 mS cm(-2)). However, centimeter-scale Nafion|graphene|Nafion devices with several graphene domains show areal H+ conductance of similar to 339 mS cm(-2) and K+ conductance of similar to 23.8 mS cm(-2) (graphene conductance for H+ is similar to 1735 mS cm(-2) and for K+ it is similar to 47.6 mS cm(-2)). Using a mathematical-transport-model and Nafion filled polycarbonate track etched supports, we systematically deconstruct the observed orders of magnitude increase in H+ conductance for centimeter-scale CVD graphene. The mitigation of defects (>1.6 nm), wrinkles and tears via interfacial polymerization results in a conductance of similar to 1848 mS cm(-2) for H+ and similar to 75.3 mS cm(-2) for K+ (H+/K+ selectivity of similar to 24.5) via intrinsic sub-nanometer proton selective defects in CVD graphene. We demonstrate atomically thin membranes with significantly higher ionic selectivity than state-of-the-art proton exchange membranes while maintaining comparable H+ conductance. Our work provides a new framework to assess H+ conductance and selectivity of large-area 2D membranes and highlights the role of intrinsic sub-nanometer proton selective defects for practical applications.