SusChEM: Surface Active Site Design for Selective Deoxygenation

许多化学过程需要在不影响其他键的情况下形成或破坏化合物中的碳-氧键的能力。 生物质向燃料和化学品的转化需要碳-氧键解离（或“脱氧”）反应，以改善生物质衍生化合物与现有精炼基础设施的相容性。 不幸的是，对脱氧有效的催化剂也经常催化导致碳损失的其他不期望的反应。 因此，设计专门从原料中去除氧气的固体材料的能力是现代催化研究的目标。在这个项目中，科罗拉多大学博尔德分校的J. Will Medlin博士正在研究如何调整催化剂表面上含氧反应物之间的相互作用，以允许从原料中特定地去除氧气。 Medlin博士还在研究催化剂纳米结构在有利于除氧反应而不是除碳反应中的作用。该项目将科学推广和培训纳入研究计划。 这些推广活动包括为本科生提供暑期研究机会，以及扩大一年一度的化学和化学工程“实地日”活动，重点是中学生动手科学实验。 在化学部化学催化项目的资助下，科罗拉多大学博尔德分校的J.威尔·麦德林博士正在研究醇类在金属表面上脱氧反应的机理。碳-氧键的选择性活化在许多应用中是重要的，包括将生物质衍生化合物转化为燃料和化学品。 鉴定对碳-氧键活化具有选择性的催化剂是特别重要的，因为碳-碳键的裂解通常导致碳损失和效率降低。 尽管某些金属表面已被鉴定为对于脱氧具有异常的活性和选择性，但表面性质和脱氧性能之间的关系尚未得到很好的理解，阻碍了设计改进的催化剂的努力。 在这个项目中，Medlin博士使用模型表面，密度泛函理论计算和负载催化剂实验相结合的实验研究，系统地研究以前与高脱氧选择性相关的因素。本计画利用同位素示踪技术，系统地研究脱氧过程中氢转移的关键步骤。脱氧选择性和动力学的测量各种钯表面，以确定与有效脱氧的几何结构。 该项目的目标是确定简单的催化剂描述符，可以通知高效催化剂的设计。该项目通过对多个级别的学生进行研究培训，以及通过Medlin博士的小组为中学生组织的年度“实地日”活动，强调STEM教育。

Many chemical processes require the ability to make or break carbon-oxygen bonds in a compound without affecting other bonds. The conversion of biomass to fuels and chemicals requires carbon-oxygen bond dissociation (or "deoxygenation") reactions to improve the compatibility of biomass-derived compounds with the existing refining infrastructure. Unfortunately, catalysts that are effective for deoxygenation also often catalyze other, undesired reactions that lead to the loss of carbon. The ability to design solid materials that specifically remove oxygen from a feedstock is thus a goal of modern catalysis research. In this project, Dr. J. Will Medlin of the University of Colorado Boulder is investigating how interactions between oxygen-containing reactants on catalyst surfaces can be tuned to allow for specific removal of oxygen from a feedstock. Dr. Medlin is also investigating the role that catalyst nanostructure plays in favoring oxygen removal reactions over those that remove carbon. The project integrates scientific outreach and training within the research program. These outreach activities include summer research opportunities for undergraduate students, as well as expansion of an annual chemistry and chemical engineering "Field Day" activity that is focused on hands-on science experiments for middle school students. With funding from the Chemical Catalysis Program of the Chemistry Division, Dr. J. Will Medlin of the University of Colorado Boulder is developing an understanding of the mechanism for deoxygenation reactions of alcohols on metal surfaces. Selective activation of carbon-oxygen bonds is important in many applications, including the conversion of biomass-derived compounds to fuels and chemicals. It is especially important to identify catalysts that are selective for carbon-oxygen bond activation, since cleavage of carbon-carbon bonds generally results in carbon loss and reduced efficiency. Although certain metal surfaces have been identified as being unusually active and selective for deoxygenation, the relationship between surface properties and deoxygenation performance is not well understood, hampering efforts to design improved catalysts. In this project, Dr. Medlin is employing a combination of experimental studies using model surfaces, density functional theory calculations, and experiments with supported catalysts to systematically investigate factors that have previously been associated with high deoxygenation selectivity. In this project, isotope tracing studies are employed to systematically investigate the mechanism for the critical hydrogen transfer step during deoxygenation. Deoxygenation selectivity and kinetics are measured for a variety of palladium surfaces to identify the geometric structures associated with efficient deoxygenation. The goal of this project is to identify simple catalyst descriptors that can inform design of efficient catalysts. This project emphasizes STEM education through the research training of students across multiple levels, as well as through an annual "Field Day" activity for middle school students organized by Dr. Medlin's group.