CHE: Combined experimental and theoretical study of solvent effects in heterogeneous catalysis

对我们未来的能源至关重要的许多化学过程依赖于多相催化，在这里，使用固体材料来帮助分子在液体状态下的化学转化。重要的多相催化过程的例子包括生物质转化为液体燃料和化学原料，燃料电池的电催化，以及用于太阳能收集和储存的光电催化剂。从固体催化剂表面和吸附在其上的分子的研究中得到的基本见解能够帮助设计新的和更有效的催化剂。Liney Arnadottir博士正在原子水平上研究催化过程，既有先进的催化剂-吸附络合物模型理论计算，也有X射线光电子能谱(XPS)测量电子结构。这项研究的更广泛影响对开发更高效的催化系统具有深远影响。与此同时，在人力资源开发方面也产生了更广泛的影响。在这项研究中，Arnadottir博士在科学和教育领域为研究生和本科生研究人员提供重要的指导。在与Arnadottir博士的互动培训中，学生们通过培养从代表性不足的群体中招募的高中生来申请和磨练自己的指导技能，这是俄勒冈州立大学为期一周的夏令营的一部分，该夏令营被称为青年科学与工程暑期体验(SEY)。SESEY夏令营期间的指导活动为未来的新一代科学领袖提供了关键的沟通技能，也使他们面临持续的STEM外展活动的需要。在这项研究中，俄勒冈州立大学的Liney Arnadottir博士结合了使用近环境压X射线光电子能谱(NAP-XPS)在溶剂环境中对醋酸和乙醇的表面表征与使用密度泛函理论(DFT)计算的理论建模。通过这个实验和计算相结合的项目，Arnadottir博士能够阐明催化中的溶剂效应，从而获得预测溶剂如何改变催化反应机理中基本步骤的速率所需的基本理解。醋酸解离是乙酸乙烯合成的第一步，具有重要的工业应用价值。醋酸和乙醇是较大含氧物中常见的官能团，具有广泛的科学意义。本研究考察了三种溶剂：水，这是一种常用的广泛使用的溶剂；1，4-二恶烷，已被证明能增强Pd(111)在水中的加氢脱氧活性；以及正庚烷，代表着一种非极性溶剂。这项研究的更广泛影响对开发更高效的催化系统具有深远影响。与此同时，在人力资源开发方面也产生了更广泛的影响。理论和实验研究是在一个紧密耦合的反馈回路中进行的，旨在提高调查效率，并作为指导研究生和本科生研究人员的学习工具。未被充分代表的高中生是研究团队的一部分，该团队通过一个小型研究项目引入，这是俄勒冈州立大学青少年科学与工程暑期体验夏令营的一部分。该项目中的所有研究生和本科生都是SESEY参与者的导师，为他们提供参与外展活动的机会，并培养他们向不同受众教授、指导和交流他们的研究的能力。这项精心设计的研究提供了对催化溶剂效应的有价值的见解，允许确定关于溶剂和吸附的反应中间体之间相互作用的趋势，同时创建了培训下一代STEM领导者的工具。

Many chemical processes essential for our energy future depend on heterogeneous catalysis, here, the use of a solid material to aid in chemical conversion of molecules in the liquid state. Examples of important heterogeneous catalysis processes include biomass conversion to liquid fuels and chemical feedstocks, electrocatalysis in fuel cells, and photoelectrocatalysts for solar energy harvesting and storage. The fundamental insights that result from a study of the solid catalyst surface and the molecules adsorbed to it are able to help in the design of new and more effective catalysts. Dr. Liney Arnadottir is studying catalytic processes at the atomic level both with advanced theoretical calculations of model catalyst-adsorbate complexes and by measuring electronic structure with x-ray photoelectron spectroscopy (XPS). Broader impacts of the research are far-reaching in the development of more efficient catalytic systems. In a parallel effort, broader impacts are made in the development of human resources. In this study, Dr. Arnadottir provides significant mentorship of graduate student and undergraduate student researchers in both the scientific and educational realms. In interactive training with the Dr. Arnadottir, students apply and hone their own mentoring skills by nurturing high school students recruited from underrepresented groups as a part of a yearly, one-week long residential summer camp at Oregon State University known as the Summer Experience in Science and Engineering for Youth (SESEY). The mentoring activities during the SESEY camp provide critical communication skills to the up-and-coming generation of new scientific leaders and also exposes them to the need for continued STEM outreach activities.In this study, Dr. Liney Arnadottir of Oregon State University combines surface characterization of acetic acid and ethanol in solvent environments using near ambient pressure X-ray Photoelectron Spectroscopy (NAP-XPS) with theoretical modeling using Density Functional Theory (DFT) calculations. With this combined experimental and computational project, Dr. Arnadottir is able to elucidate solvent effects in catalysis and thus gain the fundamental understanding required to predict how solvents change the rates of elementary steps in catalytic reaction mechanisms. Dissociation of acetic acid is the first step of vinyl acetate synthesis, which is of great industrial interest. Acetic acid and ethanol represent common functional groups in larger oxygenates with broad scientific interest. Three solvents are investigated in this study: water, which is a common and widely used solvent; 1,4 dioxane, which has been shown to enhance hydrodeoxygenation activity of Pd(111) over water; and heptane, representing a non-polar solvent. Broader impacts of the research are far-reaching in the development of more efficient catalytic systems. In a parallel effort, broader impacts are made in the development of human resources. Theoretical and experimental studies are performed in a closely-coupled feedback loop intended to improve the investigative efficiency and to serve as a learning vehicle for the mentorship of the graduate and undergraduate student researchers. Underrepresented high school students are part of the research team, brought in through a mini-research project as a part of the Summer Experience in Science and Engineering for Youth (SESEY) camp at Oregon State University. All graduate and undergraduate students in this project serve as mentors for the SESEY participants providing the opportunity to participate in outreach activities and develop their ability to teach, mentor and communicate their research to different audiences. This carefully designed study provides valuable insights into catalytic solvent effects, allows identification of trends regarding the interactions between solvent and adsorbed reaction intermediates, and simultaneously creates a vehicle for training the next generation of STEM leaders.