First-principles studies of heterogeneous electrochemistry: Electrochemical oxidation reactions over solid oxide fuel cell (SOFC) metal/electrolyte anodes

非均相电化学第一性原理研究：固体氧化物燃料电池（SOFC）金属/电解质阳极上的电化学氧化反应

• 批准号: 0756255
• 负责人: Suljo Linic
• 金额: $ 30万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-06-01 至 2012-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0756255&HistoricalAwards=false
• 关键词: First; principles; studies; heterogeneous; electrochemistry

CBET-0756255LinicSolid oxide fuel cells (SOFCs) are devices that convert chemical energy of combustible fuels into electricity. Important components of solid oxide fuel cells (SOFC) are electrodes (anode and cathode) which activate electrochemical catalytic reactions. Even though, SOFCs are very promising devices, it is astonishing how little is known about the underlying mechanisms of electrochemical reactions that govern the performance of the SOFC electrodes. For example, even for a conceptually very simple H2-oxidation reaction (H2 + O2- = H2O + 2e-) at the SOFC anode, there exist a large number of mutually conflicting elementary step mechanisms that have been proposed based on various experiments. Recent review papers in the field as well as the reports of various scientific advisory committees have emphasized the need for a better molecular level understanding of electrochemical reactions at interfaces of solid electrodes and solid electrolytes. This project will employ quantum Density Functional Theory (DFT) calculations to study elementary step mechanisms of electro-catalytic oxidation reactions over solid oxide fuel cell (SOFC) anodes. We will employ realistic model systems that account for the presence of the metal/electrolyte interface. Potential bias and electric field effects will be incorporated in our first principles calculations. While we focus on SOFC anodes, the proposed methodology is universal and it can be easily employed to address other electro-catalytic systems where solid-state electrochemistry plays a role, such as solid-state sensors, microelectronic devices, solid-state batteries, and many others. We note that the methodology outlined in this proposal has not been utilized previously to study solid-state electrochemistry.The central objective is to aid the development of predictive molecular theories aimed towards the discovery of novel SOFC material. To accomplish these objectives, we have identified four major goals: (1) we will develop a very general methodology that will allow us to study heterogeneous electro-catalytic reaction from first principles, (2) we will asses the thermodynamic feasibility of multiple elementary step mechanisms that have been proposed based on the previous experimental studies of SOFC anodes, (3) we will investigate the kinetics of the various proposed mechanisms by integrating the elementary step information into micro-kinetic models, (4) we will integrate the approach in our educational activities via multiple outreach activities and a new course development.The focus is on the theoretical studies since the solid-state electrochemical reactions are difficult to probe experimentally. The difficulties stem from: (i) an inherent experimental inaccessibility of the catalytically important metal/electrolyte interface sites, (ii) high electric fields, (iii) high potential bias, and (iii) high temperatures at which these reactions take place. The proposed theoretical framework will address these issues. We have already performed significant preliminary work demonstrating the usefulness of the proposed approach.Our central educational objective is to promote molecular approach to energy related science and technology. The educational objectives will be addressed via multiple outreach activities and the integration of the material into the curriculum. For example our group will participate in the Detroit Area Pre-College Engineering Program (DAPCEP) which offers free engineering classes to students in grades 7 and 8 from the Detroit area and the NASA Summer HighSchool Appreciation Program (SHARP) which aims to introduce high school students (grade 10 and 11) to active scientific research.The concepts proposed in this research project will also be integrated into the curriculum by introducing a cluster of courses related to energy and sustainability. This will be taught by a number of faculty members, including the PI, in the department. Furthermore, graduate students who are directly involved in the research program will be exposed to a comprehensive set of theoretical and experimental tools that will allow them to tackle most of the relevant electro-catalysis issues. In addition, we will design an educational module that will be annually presented to large groups of high school students that visit the U of Michigan during summer months. In our laboratory, we also have a three months long research internship that we offer to a promising high school student.

CBET-0756255 Linic固体氧化物燃料电池（SOFC）是将可燃燃料的化学能转化为电能的装置。固体氧化物燃料电池（SOFC）的重要组成部分是电极（阳极和阴极），其激活电化学催化反应。尽管SOFC是非常有前途的设备，但令人惊讶的是，人们对控制SOFC电极性能的电化学反应的潜在机制知之甚少。例如，即使对于SOFC阳极处的概念上非常简单的H2-氧化反应（H2 + O2- = H2O +2 e-），也存在大量基于各种实验提出的相互冲突的基本步骤机制。该领域最近的综述论文以及各种科学咨询委员会的报告强调了需要更好地理解固体电极和固体电解质界面处的电化学反应的分子水平。该项目将采用量子密度泛函理论（DFT）计算来研究固体氧化物燃料电池（SOFC）阳极上电催化氧化反应的基本步骤机制。我们将采用现实的模型系统，占存在的金属/电解质界面。电势偏置和电场效应将被纳入我们的第一原理计算。虽然我们专注于SOFC阳极，但所提出的方法是通用的，并且可以很容易地用于解决固态电化学发挥作用的其他电催化系统，例如固态传感器，微电子器件，固态电池等。我们注意到，在这个建议中概述的方法还没有使用以前的研究固态电化学。中心目标是帮助发展预测的分子理论，旨在发现新的SOFC材料。为了实现这些目标，我们确定了四个主要目标：（1）我们将开发一种非常通用的方法，使我们能够从第一原理研究多相电催化反应，（2）我们将评估基于SOFC阳极的先前实验研究提出的多个基本步骤机制的热力学可行性，（3）我们将通过将基本步骤信息整合到微观动力学模型中来研究各种提出的机制的动力学，（四）我们将通过多种外展活动和新课程的开发，将这种方法融入我们的教育活动中。重点是自固态电化学反应很难通过实验来探测。困难来自：（i）催化重要的金属/电解质界面位置的固有实验不可接近性，（ii）高电场，（iii）高电位偏压，和（iii）这些反应发生时的高温。拟议的理论框架将解决这些问题。我们已经进行了大量的初步工作，证明了所提出的方法的实用性。我们的中心教育目标是促进分子方法与能源相关的科学和技术。将通过多种外联活动和将材料纳入课程来实现教育目标。例如，我们的团队将参加底特律地区大学预科工程计划（DAPCEP），该计划为底特律地区的7年级和8年级学生提供免费工程课程，以及美国宇航局夏季高中欣赏计划（SHARP），该计划旨在向高中生介绍（10和11年级）积极的科学研究。在这个研究项目中提出的概念也将通过引入一系列课程，与能源和可持续性有关。这将是由一些教员，包括PI，在部门教。此外，直接参与研究计划的研究生将接触到一套全面的理论和实验工具，使他们能够解决大多数相关的电催化问题。此外，我们还将设计一个教育模块，每年向夏季访问密歇根大学的大批高中生展示。在我们的实验室，我们也有一个为期三个月的研究实习，我们提供给一个有前途的高中生。