高等学校化学学报 ›› 2023, Vol. 44 ›› Issue (10): 20230155.doi: 10.7503/cjcu20230155

• 物理化学 • 上一篇    下一篇

水/石墨烯界面离子吸附的分子动力学模拟: 力场参数优化与吸附机制

廖首维1, 刘炎昌1, 石泽南1, 赵道辉2, 魏嫣莹1,3(), 李理波1,3()   

  1. 1.华南理工大学化学与化工学院, 广东省绿色化学产品技术重点实验室, 广州 510640
    2.湖北大学化学与化工学院, 武汉 430062
    3.华南理工大学制浆造纸工程国家重点实验室, 广州 510640
  • 收稿日期:2023-03-30 出版日期:2023-10-10 发布日期:2023-05-31
  • 通讯作者: 魏嫣莹,李理波 E-mail:ceyywei@scut.edu.cn;celbli@scut.edu.cn
  • 作者简介:第一联系人:共同第一作者.
  • 基金资助:
    国家自然科学基金(22078104);国家重点研发计划项目(2021YFB3802500);广东省科技重点项目(2020B010188002);制浆造纸工程国家重点实验室开放课题(2022PY04);新型反应器与绿色化学工艺湖北省重点实验室开放课题(NRGC202207);中央高校基本科研业务费专项资金(2022ZYGXZR010)

Molecular Dynamics Simulation of Ion Adsorption at Water/Graphene Interface: Force Field Parameter Optimization and Adsorption Mechanism

LIAO Shouwei1, LIU Yanchang1, SHI Zenan1, ZHAO Daohui2, WEI Yanying1,3(), LI Libo1,3()   

  1. 1.Guangdong Provincial Key Lab of Green Chemical Product Technology,School of Chemistry and Chemical Engineering,South China University of Technology,Guangzhou 510640,China
    2.College of Chemistry and Chemical Engineering,Hubei University,Wuhan 430062,China
    3.State Key Laboratory of Pulp and Paper Engineering,South China University of Technology,Guangzhou 510640,China
  • Received:2023-03-30 Online:2023-10-10 Published:2023-05-31
  • Contact: WEI Yanying, LI Libo E-mail:ceyywei@scut.edu.cn;celbli@scut.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(22078104);the National Key Research and Development Program, China(2021YFB3802500);the Science and Technology Key Project of Guangdong Province, China(2020B010188002);the Opening Project of the State Key Laboratory of Pulp and Paper Engineering, China(2022PY04);the Opening Project of the Hubei Key Laboratory of Novel Reactor and Green Chemical Technology, China(NRGC202207);the Fundamental Research Funds for the Central Universities, China(2022ZYGXZR010)

摘要:

受限在二维纳米孔道的盐溶液的研究对离子输运与筛分、 超级电容等领域具有重要意义, 而分子动力学(MD)模拟已成为其中重要的手段. 但通常MD模拟力场却很难准确描述石墨烯等二维材料与离子之间的离子-π相互作用; 溶剂效应对离子在材料表面吸附的调控作用也缺乏深入研究. 针对Li+, Na+, K+, Mg2+, Ca2+, Cl-离子与石墨烯材料, 本文基于平均力势(PMF)发展了模拟它们之间相互作用的力场参数. 使用该力场模拟的(溶液中)石墨烯表面离子吸附自由能与量子化学计算结果一致, 验证了其准确性. 进一步发现离子水合半径、 离子接近石墨烯时水合数的拐点、 PMFwat(溶剂对离子吸附在石墨烯表面PMF的贡献)极小值位置及石墨烯表面水层位置之间有明显关联. 在此基础上阐明了离子脱水及石墨烯表面水层状分布对PMFwat的调控作用. 模拟了1 mol/L盐溶液/石墨烯界面体系. 以上体系使用通常力场参数模拟时, 离子在石墨烯表面吸附都很微弱, 这表明离子-π相互作用对准确模拟盐溶液-石墨烯体系不可或缺.

关键词: 石墨烯, 离子吸附, 力场参数, 平均力势, 分子动力学模拟

Abstract:

The researches of salt solution confined in two-dimensional nanochannels are of great significance in a wide range of fields such as ion transport and sieving, supercapacitor, etc., and molecular dynamics(MD) simulations in these research have become an important tool. However, it is difficult for common MD force fields(FFs) to accurately describe the ion-π interactions between two-dimensional materials(e.g., graphene) and ions. In addition, the role of solvent effects on regulating ion adsorption on the solution/material interface also lacks in-depth studies. In this work, we have developed the FF parameters for the interactions between Li+, Na+, K+, Mg2+, Ca2+, Cl ions and graphene based on the potentials of mean force(PMFs). The ion adsorption free energies on the graphene surface(in solution) simulated using the as-developed FF coincided with the quantum chemical calculations, which verified the accuracy of the as-developed FF. Furthermore, significant correlations were found between the ion hydration radius, the inflection point of the hydration number as the ion approaches the graphene, the position of the PMFwat(the contributions of water to the PMFs of ion adsorption on graphene surface) minima and the position of the water layer on the graphene surface, elucidating the effects of ion dehydration and the water layers on graphene surface on PMFwat. In addition, the salt solution(concentration of 1 mol/L)/graphene interface systems were simulated. For the above systems, ions simulated by common MD FFs hardly absorb on graphene surface, which indicates that ion-π interactions are indispensable for accurately simulating the salt solution-graphene systems.

Key words: Graphene, Ion adsorption, Force field parameter, Potential of mean force, Molecular dynamics simulation

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