Collaborative Research: Multiscale atomistic modeling tools for electrocatalytic systems

科学价值：随着传统化石燃料能源的枯竭，新的能源转换和化学能源存储方法将需要为便携式和固定式应用提供能源。燃料电池能有效地将化学能转化为电能。电解应用逆转了这一过程，并将来自可再生能源（如风能或太阳能）的电力以化学形式储存起来供以后使用。在化学形式和电形式之间转换能量的效率是由发生在器件电极上的原子过程决定的。这些过程很难用常规实验来探测。这些过程的表征是使用原子和量子级计算方法实现的。目前用于评估电极表面反应性的建模方法有两个主要限制：无法估计电子转移反应的速率，以及缺乏可以描述化学反应和电荷转移的原子力场，但保留捕获相关界面现象所需的厚度。宾夕法尼亚州立大学的Michael Janik和Janna Maranas教授以及佛罗里达大学的Susan Sinnott教授已经获得了国家科学基金会催化和生物催化项目的奖励，以解决这些限制。第一个限制将通过使用基于量子力学的方法开发电子转移速率常数的可转移方法来解决。该方法将与二氧化碳还原反应（与将电能和废弃二氧化碳转化为化学燃料相关）和氧气还原反应（与燃料电池相关）的实验数据进行应用和验证。该方法将与实验相结合，进一步应用于生物原料电催化合成高价值化学品的反应机理。第二个限制将通过电极和溶剂的可变部分电荷的反应性分子力场来解决。针对铜和铂电极与氢碱电解质接触的情况，将开发电荷优化多体反应电位。分子动力学计算将评估电化学界面，包括溶剂结构和电荷分布。这些多尺度原子建模工具能够确定电化学反应机制。它们将应用于三个特定的电催化应用，以评估一系列特定的反应假设。更广泛的影响：这项工作的更广泛影响确保了一个清洁能源的未来，在这个未来中，可再生能源和化学储能共同努力，为可持续能源提供了一种有效、实用的方法。该项目开发了一个联合量子化学和反应分子动力学框架来模拟电化学界面，促进合理设计用于改进电池、燃料电池和电网级电化学储能的材料。考虑到这一点，教育活动的设计是为了激励学生在能源相关领域从事职业。研究生将受益于两所大学的跨学科研究项目，并熟练掌握多种计算机模拟方法。部分提议的工作将被打包为宾夕法尼亚州立大学和佛罗里达大学的本科项目，包括宾夕法尼亚州立大学少数族裔本科生研究经验和科学与工程研究项目中代表性不足的群体。研究机会将通过佛罗里达大学提供给高中生。开发的计算机模拟方法将广泛分布到计算界，允许其他人将开发的技术应用于本提案范围之外的电化学问题。

ABSTRACTCollaborative Proposals #1264104 - Susan B. Sinnott #1263951 - Michael J. Janik Scientific Merit: As traditional fossil fuel sources of energy are depleted, new energy conversion and chemical energy storage approaches will be needed to supply energy for both portable and stationary applications. Fuel cells offer efficient conversion of chemical to electrical energy. Electrolysis applications reverse this process and store electricity from renewable sources, such as the wind or sun, in chemical form for later use. The efficiency of converting energy between chemical and electrical forms is dictated by atomistic processes that occur at device electrodes. These processes are difficult to probe with conventional experiments. The characterization of these processes is enabled using atomic and quantum level computational methods. There are two major limitations in current modeling approaches for evaluating reactivity of electrode surfaces: the inability to estimate rates for electron transfer reactions and the lack of atomistic force fields that can describe chemical reactions and charge transfer, yet retain the thickness required to capture relevant interfacial phenomena. Professors Michael Janik and Janna Maranas of Pennsylvania State University and Susan Sinnott of the University of Florida have received an award from the National Science Foundation Catalysis & Biocatalysis Program to tackle these limitations. The first limitation will be addressed through the development of a transferable method for electron transfer rate constants using methods based on quantum mechanics. This method will be applied and validated versus experimental data for the carbon dioxide reduction reaction (of relevance for converting electrical energy and waste carbon dioxide into a chemical fuel) and the oxygen reduction reaction (of relevance in fuel cells). The method will be further applied, in collaboration with experiment, to evaluate the reaction mechanism in the electrocatalytic synthesis of high value chemicals from bio-derived feedstock. The second limitation will be addressed through a reactive molecular force field with variable partial charges for both electrode and solvent. Charge optimized many-body reactive potentials will be developed for copper and platinum electrodes in contact with alkali hydroxide electrolytes. Molecular dynamics calculations will evaluate electrochemical interface, including solvent structure and charge distribution. These multiscale atomistic modeling tools enable definitive identification of electrochemical reaction mechanisms. They will be applied to three specific electrocatalytic applications to evaluate a series of reaction specific hypotheses. Broader Impacts: The broader impacts of this work secure a clean energy future in which renewable energy and chemical energy storage work together to provide an efficient, practical approach to sustainable energy. This project develops a joint quantum chemistry and reactive molecular dynamics framework to model electrochemical interfaces, facilitating rational design of materials for improved batteries, fuel cells, and grid-level electrochemical energy storage. With this in mind, educational activities are designed to motivate students to pursue careers in energy related fields. Graduate students will benefit from an inter-disciplinary research project at two universities, and become skilled in multiple computer simulation methods. Portions of the proposed work will be packaged as undergraduate projects at both Penn State and the University of Florida, including underrepresented groups through the Penn State Minority Undergraduate Research Experience and Women in Science and Engineering Research programs. Research opportunities will be provided to high school students through the U. of Florida. The developed computer simulation methods will be broadly distributed to the computational community, allowing others to apply the techniques developed to electrochemical problems outside the scope of this proposal.