We characterize the structure–property relationship of alkali metal elements in oxygen-passivated graphene pores using the density functional theory that accounts for quantum mechanical effects and charge transfer. Our description is based on the structural and electronic properties of the system and shows common trends among the different alkali metals and pores. We find that these nanopores which serve as docking sites for alkali metal elements give the strongest binding when the size of the pore is similar to the element's van der Waals radius. A linear correlation between the binding energy and the energy location of the alkali element valence state is found for all elements and pores. Analysis of the charge transfer reveals that alkali adsorption increases the local charge in the perimeters of the pore by amounts that depend on the geometry. Moreover, charge distributions in pristine graphene resemble those of an ideal conductor despite its semimetallic character and atomic thickness while oscillations in the vicinity of O-passivated nanopores are observed. Our results suggest that charge transfer is localized within a few nanometers of the pore and, therefore, allude to high density energy storage. The outcomes of this work are significant towards the application of porous graphene as effective membranes for ion filtration of water and electrode applications.

中文翻译：

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石墨烯中碱金属元素与氧钝化纳米孔之间相互作用的首要原理研究†

我们使用解释量子力学效应和电荷转移的密度泛函理论来表征氧钝化石墨烯孔中碱金属元素的结构-性质关系。我们的描述基于系统的结构和电子特性，并显示了不同碱金属和孔之间的共同趋势。我们发现，当孔的尺寸类似于元素的范德华半径时，这些用作碱金属元素对接位点的纳米孔具有最强的结合力。对于所有元素和孔，发现结合能与碱元素价态的能量位置之间存在线性关系。电荷转移的分析表明，碱吸附增加了孔周边的局部电荷，其数量取决于几何形状。此外，原始石墨烯中的电荷分布尽管具有半金属特性和原子厚度，却类似于理想导体的电荷分布，同时观察到O钝化纳米孔附近的振荡。我们的结果表明电荷转移位于孔的几纳米内，因此暗示了高密度能量存储。这项工作的成果对于多孔石墨烯作为水和电极应用中离子过滤的有效膜的应用具有重要意义。尽管其半金属特性和原子厚度，原始石墨烯中的电荷分布类似于理想导体的电荷分布，同时观察到O钝化纳米孔附近的振荡。我们的结果表明电荷转移位于孔的几纳米内，因此暗示了高密度能量存储。这项工作的成果对于多孔石墨烯作为水和电极应用中离子过滤的有效膜的应用具有重要意义。尽管其半金属特性和原子厚度，原始石墨烯中的电荷分布类似于理想导体的电荷分布，同时观察到O钝化纳米孔附近的振荡。我们的结果表明电荷转移位于孔的几纳米内，因此暗示了高密度能量存储。这项工作的成果对于多孔石墨烯作为水和电极应用中离子过滤的有效膜的应用具有重要意义。