We investigate aqueous proton penetration behavior across a newly synthesized nanoporous two-dimensional conjugated aromatic polymer (2D-CAP) membrane using extensive ReaxFF reactive molecular dynamics simulations. We found that the proton penetration energy barrier across 2D-CAP is twice as high as that of graphtetrayne, even though 2D-CAP exhibits a larger pore size. Detailed analysis indicates that the anomalous high proton conduction energy barrier of 2D-CAP originates from its unique atomic nanopore structure. The hydrogen atoms at the periphery of the 2D-CAP nanopores can form a stable local hydrogen bond network with water molecules inside or surrounding the nanopores. The mobility of water molecules involved in this local hydrogen bond network will be significantly lowered, and the proton transportation process across the nanopores will thus be impeded. Our results show that the proton penetration behavior across nanoporous 2D materials is influenced not only by the pore size, but also by the decorated atoms or functional groups at the pore edges. Hydrogen atoms at the periphery of nanopores with certain geometry can form a stable local hydrogen bond network with neighboring water molecules, further hampering the proton conductivity.

中文翻译：

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跨纳米多孔二维共轭芳族聚合物膜的异常质子传导行为。

我们使用广泛的ReaxFF反应分子动力学模拟研究跨新合成的纳米多孔二维共轭芳族聚合物（2D-CAP）膜的水质子渗透行为。我们发现，即使2D-CAP表现出较大的孔径，其跨2D-CAP的质子穿透能垒也是图四炔的两倍。详细的分析表明2D-CAP的异常高质子传导能垒源自其独特的原子纳米孔结构。2D-CAP纳米孔外围的氢原子可以与纳米孔内部或周围的水分子形成稳定的局部氢键网络。参与该局部氢键网络的水分子的迁移率将大大降低，从而将阻止质子跨纳米孔的传输过程。我们的结果表明，质子在纳米多孔2D材料中的渗透行为不仅受孔径的影响，还受孔边缘修饰的原子或官能团的影响。具有一定几何形状的纳米孔外围的氢原子可与相邻的水分子形成稳定的局部氢键网络，从而进一步阻碍了质子的电导率。