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Electrocatalysis at the electrode-electrolyte interface: a combined DFT and classical force-field approach

电极-电解质界面的电催化：结合 DFT 和经典力场方法

基本信息

批准号：
1939464
负责人：
Scott Milner
金额：
$ 36.84万
依托单位：
Pennsylvania State Univ University Park
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-07-15 至 2024-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1939464&HistoricalAwards=false
关键词：
Electrocatalysis electrode electrolyte interface combined

项目摘要

Electrochemistry offers a route to manufacturing fuels and chemicals from renewable or sustainable energy sources such as solar, wind, or hydroelectric power. The efficiency, rates, and product selectivity of such electrochemical processes can be further improved by incorporating catalysts into the electrochemical technology. Although effective, electrocatalytic manufacturing processes are highly complex, making it difficult to predict the best combinations of catalytic materials and operating conditions needed for optimal performance. The project will develop theoretical and mathematical methods to understand the energetics of electrocatalytic reactions in liquid solvents, thereby facilitating the search for improved catalysts and manufacturing processes. The project also involves training of students at various educational levels and outreach to underrepresented groups. Computational methods to model electrocatalytic processes at the electrode/electrolyte interface are essential to guide rational design. Much progress has been made in theoretical descriptions of surface-bound reactant and product states, particularly using density functional theory (DFT). More recently, advances in describing electrocatalytic transition states have enabled estimates of reaction barriers. However, in these advances the description of the surrounding electrolyte is comparatively primitive, despite the evident importance of solvation effects on reaction rates. The project combines state-of-the-art DFT methods to compute the transition state, with classical molecular dynamics (MD) simulation methods to compute solvation free energies. The enabling concept is to treat the DFT transition state described at the metal/vacuum interface as a molecule, to be inserted into the electrolyte in the double layer. MD simulation methods have been developed for solvation free energies of molecules in solution, by computing the thermodynamic work required to slowly "turn on" the interactions with surrounding fluid. These methods will be applied to the transition state itself, as well as to the surface-bound reactants and products. Relatively polar reactants, transition states, and products should more strongly interact with solvent and electrolyte ions, and their free energies lowered accordingly, with corresponding effects on reaction barriers. These important solvation effects on barriers and reaction rates depend crucially on proper averaging over local arrangements of water molecules and ions near the surface. Atomistic MD simulations are uniquely suited to describe and average over these local arrangements. The first reactions to be studied with the new methods will include electrocatalytic hydrogen oxidation and propanol reduction, reactions of technical relevance for fuel cells and biomass electroreduction. The developed approach will be validated against available experimental data, including solution phase propanol dehydration barriers, interfacial water structure, double-layer capacitance, hydrogen oxidation barriers on single-crystal Pt electrodes, and propanol electroreduction barriers. Both graduate and undergraduate students will develop and apply the proposed methods, and receive broad education in electrochemistry, electronic structure, and molecular modeling. Both investigators will continue their strong record of mentoring undergraduates in research, which together has resulted in 48 advised undergraduates who have co-authored 22 peer reviewed publications over the past 5 years.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

电化学提供了一种从可再生或可持续能源（如太阳能，风能或水力发电）制造燃料和化学品的途径。这种电化学过程的效率、速率和产物选择性可以通过将催化剂结合到电化学技术中来进一步改进。虽然有效，但电催化制造工艺非常复杂，使得难以预测催化材料的最佳组合和最佳性能所需的操作条件。该项目将开发理论和数学方法，以了解液体溶剂中电催化反应的能量学，从而促进对改进催化剂和制造工艺的研究。该项目还包括培训各级教育的学生，并向代表性不足的群体开展外联活动。在电极/电解质界面模拟电催化过程的计算方法是必不可少的，以指导合理的设计。在表面结合反应物和产物态的理论描述方面取得了很大的进展，特别是使用密度泛函理论（DFT）。最近，在描述电催化过渡态的进展，使反应势垒的估计。然而，在这些进展的描述周围的电解质是比较原始的，尽管溶剂化反应速率的影响的明显重要性。该项目结合了最先进的DFT方法来计算过渡态，经典的分子动力学（MD）模拟方法来计算溶剂化自由能。使能概念是将在金属/真空界面处描述的DFT过渡态作为分子处理，以插入到双层中的电解质中。分子动力学模拟方法已经被开发用于溶液中分子的溶剂化自由能，通过计算缓慢地“打开”与周围流体的相互作用所需的热力学功。这些方法将适用于过渡态本身，以及表面结合的反应物和产物。相对极性的反应物、过渡态和产物应该与溶剂和电解质离子更强地相互作用，并且它们的自由能相应地降低，对反应势垒具有相应的影响。这些重要的溶剂化效应的障碍和反应速率取决于关键的适当平均超过当地安排的水分子和离子的表面附近。原子分子动力学模拟是唯一适合于描述和平均这些本地安排。用新方法研究的第一批反应将包括电催化氢氧化和丙醇还原，与燃料电池和生物质电还原技术相关的反应。所开发的方法将验证现有的实验数据，包括溶液相丙醇脱水障碍，界面水结构，双层电容，氢氧化障碍单晶Pt电极，和丙醇电还原障碍。研究生和本科生都将开发和应用所提出的方法，并接受电化学，电子结构和分子建模方面的广泛教育。两位研究人员将继续他们在指导本科生研究方面的良好记录，在过去的5年里，共有48名被推荐的本科生共同撰写了22篇同行评审的出版物。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。