Specific ion effects at graphitic interfaces
Specific ion effects at graphitic interfaces
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DOI：
10.1038/s41467-019-12854-7
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发表时间：
2019-10
影响因子：
16.6
通讯作者：
Cheng Zhan;M. Ceron;S. Hawks;M. Otani;B. Wood;T. Pham;M. Stadermann;P. Campbell
中科院分区：
文献类型：
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作者：
Cheng Zhan;M. Ceron;S. Hawks;M. Otani;B. Wood;T. Pham;M. Stadermann;P. Campbell
提高对石墨界面处水溶液的理解对于能量储存和水脱盐至关重要。然而，许多机制的细节仍然不清楚，包括界面结构和响应如何由施加电压下的溶剂化离子的固有性质决定。在这项工作中，我们结合联合收割机混合第一性原理/连续模拟与电化学测量，以调查吸附的几种碱金属阳离子在界面处与石墨烯和石墨烯狭缝孔内。我们证实，吸附能随离子半径增加，同时高度依赖于孔径。此外，与传统的电化学模型相比，我们发现，界面电荷转移有助于不可忽视的这种相互作用，并可以进一步加强限制。我们的结论是，测得的界面电容的趋势，从电压，限制，和特定的离子效应，包括离子水合和电荷转移之间的复杂的相互作用的结果。
Improved understanding of aqueous solutions at graphitic interfaces is critical for energy storage and water desalination. However, many mechanistic details remain unclear, including how interfacial structure and response are dictated by intrinsic properties of solvated ions under applied voltage. In this work, we combine hybrid first-principles/continuum simulations with electrochemical measurements to investigate adsorption of several alkali-metal cations at the interface with graphene and within graphene slit-pores. We confirm that adsorption energy increases with ionic radius, while being highly dependent on the pore size. In addition, in contrast with conventional electrochemical models, we find that interfacial charge transfer contributes non-negligibly to this interaction and can be further enhanced by confinement. We conclude that the measured interfacial capacitance trends result from a complex interplay between voltage, confinement, and specific ion effects-including ion hydration and charge transfer.