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Modeling of the electric double layer at metal oxide electrode/electrolyte interfaces with density functional theory based molecular dynamics

基于密度泛函理论的分子动力学模拟金属氧化物电极/电解质界面的双电层

基本信息

批准号：
263270542
负责人：
Dr. Chao Zhang
金额：
--
依托单位：
Yusuf Hamied Department of Chemistry
依托单位国家：
德国
项目类别：
Research Fellowships
财政年份：
2014
资助国家：
德国
起止时间：
2013-12-31 至 2016-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/263270542?language=en
关键词：
Modeling electric double layer metal

项目摘要

Transition metal oxides play a prominent role in the design of new, efficient (photo) electrocatalysts demanded by the increased energy need and the related environmental issues in Germany and worldwide. Most earth-abundant metal oxides are only stable in alkaline solution (pH 14). Modeling and simulation of the electric double layer (EDL) formed by deprotonation of adsorbed water and hydroxide ions at the metal oxide electrode/electrolyte interfaces is therefore an integral part of optimizing the cost efficiency of energy conversion. However, the lack of a detailed atomistic understanding of metal oxide electrochemical interfaces under operating conditions considerably hampers progresses. Here, as the core objective of the project, I propose to develop and investigate the modeling of protonic EDL's using density functional theory (DFT) based molecular dynamics (MD) with explicit treatment of solvent. The focus will be on the dielectric properties of the EDL. As an example of high technological interest for photoelectrochemical energy conversion, we will study the protonic EDL at a model TiO2/electrolyte interface under the flatband conditions. By combining concepts of (single) electrode potentials in electrochemistry and Berry phase polarization in periodic systems for the first time, we expect to achieve a more realistic modeling of the EDL and ionic screening in the electrolytic solution. In particular, the proposed approach would enable us to charge the double layer at fixed chemical composition and compute the polarization as a new observable as well as the Helmholtz capacitance and the detailed spatial variation of the dielectric response in the double layer. This novel method will represent a considerable leap forward with respect to traditional continuum theories and current simplified atomistic supercell models. It would further lay down a valuable basis for future research towards a mechanistic understanding of the coupling of EDL with electrocatalytic processes, which is highly relevant for the design of efficient and economical electrocatalysts and photocatalysts.

过渡金属氧化物在设计新型高效（光电）电催化剂方面发挥着重要作用，以满足德国和世界各地日益增长的能源需求和相关的环境问题。大多数地球上丰富的金属氧化物只在碱性溶液（pH值14）中稳定。因此，对金属氧化物电极/电解质界面上吸附的水和氢氧化物离子脱质子形成的双电层（EDL）进行建模和仿真是优化能量转换成本效率的重要组成部分。然而，缺乏对操作条件下金属氧化物电化学界面的详细的原子性理解，极大地阻碍了研究的进展。在这里，作为该项目的核心目标，我建议利用基于密度泛函理论（DFT）的分子动力学（MD）开发和研究质子EDL的模型，并明确处理溶剂。重点将放在EDL的介电特性上。作为光电化学能量转换的一个高技术兴趣的例子，我们将在平带条件下研究模型TiO2/电解质界面上的质子EDL。通过首次将电化学中的（单）电极电位概念与周期系统中的Berry相极化概念相结合，我们期望实现电解溶液中EDL和离子筛选的更真实的建模。特别地，所提出的方法将使我们能够在固定的化学成分下对双层进行充电，并计算极化作为一种新的观测值，以及双层中介电响应的亥姆霍兹电容和详细的空间变化。与传统的连续统理论和目前简化的原子超级单体模型相比，这种新方法将是一个相当大的飞跃。这将为进一步了解EDL与电催化过程耦合的机理研究奠定宝贵的基础，这对设计高效、经济的电催化剂和光催化剂具有重要意义。