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.

在化学催化计划中，俄勒冈大学的克里斯托弗·H·亨登（Christopher H. Hendon）正在研究通过过渡金属簇介导的光催化二氧化碳（CO2）还原。二氧化碳还原是一种重要的化学反应，因为它可以降低大气中的二氧化碳水平，同时还会形成有价值的产品，例如正式的酸和甲醛。二氧化碳转化率是一种困难的化学转化，因为所需的产物（例如形式的酸和甲醛）相互竞争，形成它们所需的质子和电子数量不同。为了克服这个问题，Hendon博士将使用计算建模来研究使用无机簇对CO2的光催化还原，这将为反应提供精确数量的质子和电子。该研究将研究这些金属簇如何用于饥饿反应物（H•）以选择目标产物的氢化反应，并证明支持金属簇的配体允许金属位点的能量调整。如果成功的话，这项工作有可能指导实验者达到更具选择性的条件，以减少所需产品的二氧化碳。此外，这项计算工作可能在其他有问题的氢化中被证明是有用的，这会受到选择性问题的困扰，包括烷烃和炔烃的调节降低。这项工作将与Hendon博士现有的呼吸提取物电催化计划协同，这是一个成功的计划，该计划通过咖啡镜头教授基本的化学和物理学。该奖项将支持针对非传统学生的正式课程的开发，该课程将成为开源和社区维护的。虽然可以通过使用H2的常规氢化来促进最重要的CO2减少反应，但可以通过使用其他H源来实现选择性。一种承诺路线涉及转移氢化，从而从一个物种到另一种物种施用氢。该提案旨在证明使用金属有机框架（MOF）中原子精确的无机簇可以实现选择性CO2转移氢化（还原）。在该奖项中，亨登博士将使用计算化学检查一个异质多核过渡金属催化剂家族，并将研究从供体（例如醇，水等）中提取氢的一般机制，并转移到受体中（例如CO2）。反应机制可能取决于供体/催化剂/受体的PKA及其氧化还原电位的差异。从这些研究中，Hendon组将通过群集调节搜索具有可调数量的可调节氢原子的化学选择性的目标MOF簇。这些研究共同基于电子能量比对，共同渴望产生一般设计原理，用于选择供体，受体和基于MOF的催化剂。通过与实验者的合作，该工作旨在产生一个二氧化碳的降低光催化剂家族，从大量的供体中获取其H••该奖项反映了NSF的法定任务，并通过使用基金会的智力优点和更广泛的影响来评估NSF的法定任务，并被认为是珍贵的支持。