Multi-scale modeling of electrochemical interfaces: New methods and applications to RuO2 surfaces

电化学界面的多尺度建模：RuO2 表面的新方法和应用

• 批准号: 410880363
• 负责人: Dr. Daniel Opalka
• 金额: --
• 依托单位: National Natural Science Foundation of China
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/410880363?language=en
• 关键词: Multi; scale; modeling; electrochemical; interfaces

The computational simulation of electrochemical interfaces is a key methodology to understand electrochemical processes at a molecular level. Solid/liquid interfaces are subject to significant complexity due to the interplay of electrostatic interactions, charge transfer processes and the formation of an electrical double layer. Considering the intricate structure and dynamical processes at electrochemical interfaces and currently available computational resources, the simulation of realistic models with ab initio electronic structure theory is infeasible. In this project we develop new simulation protocols which combine simulation methods at multiple scales to achieve predictive, yet computationally inexpensive, models of electrochemical reactions at catalyst surfaces.As a prototypical example we focus on the electrochemical water oxidation reaction at RuO2/electrolyte interfaces. RuO2 is one of the most efficient catalysts for the oxygen evolution reaction in electrolyzers, but catalyst morphology and stability at operating conditions are still under debate. The intrinsic multiscale nature of electrochemical processes, which involve fast charge redistribution but also electrolyte diffusion processes at a nanosecond timescale, are addressed by complementary methods combining density functional and classical theories. Based on initial screening of surface structures using surface free energy calculations by ab initio thermodynamics, selected structures are used for the development of quantum/molecular mechanics (QM/MM) and implicit solvation techniques. The implemented methods are validated by experimental data and ab initio molecular dynamics simulations treating all components of a system strictly at the same level of density functional theory. From simulations of RuO2/electrolyte interfaces at open-circuit and operating conditions we address fundamental questions concerning morphology, stability and activity in relation to potential, pH and electrical double layer.

电化学界面的计算模拟是从分子水平上理解电化学过程的关键方法。由于静电相互作用、电荷转移过程和双电层形成的相互作用，固/液界面具有极大的复杂性。考虑到电化学界面复杂的结构和动力学过程以及现有的计算资源，用从头算电子结构理论模拟现实模型是不可行的。在这个项目中，我们开发了新的模拟协议，将多尺度的模拟方法结合起来，以获得可预测的、但计算成本较低的催化剂表面电化学反应模型。作为典型例子，我们重点关注RuO2/电解液界面上的电化学水氧化反应。RuO2是电解槽析氧反应最有效的催化剂之一，但催化剂的形态和在操作条件下的稳定性仍存在争议。通过结合密度泛函和经典理论的互补方法，讨论了电化学过程的内在多尺度性质，包括快速电荷再分配和纳秒时间尺度上的电解液扩散过程。在利用从头算热力学的表面自由能计算初步筛选表面结构的基础上，选定的结构被用于发展量子/分子力学(QM/MM)和隐式溶剂化技术。实验数据和从头算分子动力学模拟在密度泛函理论的同一水平上严格处理了系统的所有组分，验证了所实现的方法。通过对RuO2/电解液界面在开路和操作条件下的模拟，我们解决了与电位、pH和双电层有关的形态、稳定性和活性的基本问题。