CAREER: Photocatalytic Transfer Hydrogenation of CO2 Using Transition Metal Cluster Arrays

职业：使用过渡金属簇阵列进行二氧化碳光催化转移氢化

• 批准号: 2237345
• 负责人: Christopher Hendon
• 金额: $ 57.2万
• 依托单位: University of Oregon Eugene
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-06-01 至 2028-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2237345&HistoricalAwards=false
• 关键词: CAREER; Photocatalytic; Transfer; Hydrogenation; CO2

With support from the Chemical Catalysis Program in the Division of Chemistry, Christopher H. Hendon of the University of Oregon is studying photocatalytic carbon dioxide (CO2) reduction mediated by transition metal clusters. Carbon dioxide reduction is an important chemical reaction because it can reduce atmospheric CO2 levels, while also forming valuable products like formic acid and formaldehyde. CO2 conversion is a difficult chemical transformation because the desired products (e.g. formic acid and formaldehyde) are formed in competition with one another, differing in the number of protons and electrons required to form them. To overcome this problem, Dr. Hendon will use computational modeling to study photocatalytic reduction of CO2 with inorganic clusters, which will provide precise numbers of protons and electrons for the reaction. The research will examine how these metal clusters can be used to starve hydrogenation reactions of reactants (H•) to select for target products, and demonstrate that the ligands that support the metal clusters allow for energetic tuning of the metal sites. If successful, this work has the potential to guide experimentalists to achieve more selective conditions for CO2 reduction to the desired product. Moreover, this computational work may prove useful in other problematic hydrogenations, plagued by selectivity issues, including the regioselective reduction of alkenes and alkynes. This work will synergize with Dr. Hendon’s existing program in electrocatalysis of beverage extracts, a successful program that teaches fundamental chemistry and physics through the lens of coffee. This award will support the development of a formal curriculum for non-traditional students, that will be made open-source and community-maintained.While the the all-important CO2 reduction reaction can be promoted through conventional hydrogenation with H2, selectivity can be achieved by using other H-sources. One promising route involves transfer hydrogenation, whereby hydrogen commutes from one species to another. This proposal seeks to demonstrate that selective CO2 transfer hydrogenation (reduction) can be achieved using atomically precise inorganic clusters in metal-organic frameworks (MOFs). In this award, Dr. Hendon will use computational chemistry to examine a family of heterogeneous polynuclear transition metal catalysts and will study the general mechanism in which hydrogen is extracted from donors (e.g. alcohols, water, etc.) and transferred to acceptors (e.g. CO2). The reaction mechanism likely depends on differences in pKa of the donor/catalyst/acceptor, as well as their redox potentials. From these studies, the Hendon group will search for target MOF clusters with improved chemical selectivity with tunable numbers of available hydrogen atoms through cluster modulation. Together, these studies aspire to yield a general design principle for selection of donor, acceptor, and MOF-based catalysts, based on electron energy alignments. Through collaboration with experimentalists the work aims to generate a family of CO2 reduction photocatalysts that source their H• from abundant donors.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.

在化学系化学催化计划的支持下，俄勒冈大学的克里斯托弗·H·亨登正在研究过渡金属簇介导的光催化二氧化碳(CO2)还原。二氧化碳减少是一个重要的化学反应，因为它可以降低大气中的二氧化碳水平，同时也会形成有价值的产品，如甲酸和甲醛。二氧化碳转化是一种困难的化学转化，因为所需的产物(如甲酸和甲醛)是在相互竞争中形成的，形成它们所需的质子和电子数量不同。为了克服这个问题，亨登博士将使用计算模型来研究无机簇对二氧化碳的光催化还原，这将为反应提供精确的质子和电子数量。这项研究将研究如何利用这些金属簇来抑制反应物(H·)的加氢反应，以选择目标产物，并证明支撑金属簇的配体允许对金属位置进行能量调节。如果成功，这项工作有可能指导实验者实现更具选择性的条件，将二氧化碳减少到所需的产品。此外，这项计算工作可能会被证明对其他有问题的加氢反应有用，这些问题受到选择性问题的困扰，包括区域选择性地还原烯烃和炔烃。这项工作将与亨登博士现有的饮料提取物电催化项目相配合，这是一个成功的项目，通过咖啡的镜头教授基础化学和物理。该奖项将支持为非传统学生开发正式课程，使其成为开源和社区维护的课程。虽然最重要的二氧化碳还原反应可以通过传统的氢气加氢反应来促进，但选择性可以通过使用其他氢源来实现。一条很有希望的路线涉及转移氢化，即氢从一种物种转移到另一种物种。这项提议试图证明，利用金属有机骨架(MOF)中原子上精确的无机簇合物，可以实现选择性的二氧化碳转移加氢(还原)。在这一奖项中，亨登博士将使用计算化学来研究一系列多核过渡金属催化剂，并将研究从供体(如醇、水等)中提取氢的一般机理。并转移到接受者(例如二氧化碳)。反应机理可能取决于给体/催化剂/受体的pKa的差异以及它们的氧化还原电位。从这些研究中，Hendon小组将通过团簇调制寻找具有改进的化学选择性和可用氢原子数量可调的目标MOF团簇。综上所述，这些研究旨在为基于电子能量排列的给体、受体和MOF基催化剂的选择提供一个通用的设计原则。通过与实验者的合作，这项工作旨在产生一系列二氧化碳还原光催化剂，从大量的捐赠者那里获得H·。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。