CAS:Improving the Activity of Homogeneous Mn Catalysts for the Oxygen Reduction Reaction

在化学系化学催化项目的支持下，弗吉尼亚大学的Charles W. Machan正在研究分子锰化合物催化还原双氧的方法。在燃料电池等设备中，双氧的还原可以用于化学键产生能量，在这些设备中，它是与化学燃料氧化配对产生能量的首选反应。为了使这些系统具有可部署性和可扩展性，必须开发由地球上丰富的材料制成的催化剂。虽然已知锰与双氧有很强的相互作用，但由这种金属制成的催化剂相对较少，因为基于锰的有效加速催化的策略尚不发达。这些关于双氧还原的研究旨在开发更好的锰催化剂的设计原则，以达到与其他过渡金属竞争的足够性能指标。这些努力的一个重要部分是一个以研究为重点的教育推广计划，为学生提供科学传播方面的培训。还将开发工具包，为各级本科生提供以研究为基础的实验室体验。正在研究的研究目标和正在发展的教育组成部分正在通过满足对新能源技术日益增长的需要和使学生在职业生涯早期阶段熟悉能源研究来解决社会的重要优先事项。在这个奖项下，弗吉尼亚大学的Machan研究小组正在研究分子锰化合物催化还原双氧。锰作为一种丰富的过渡金属，与双氧结合较强，有很大的潜力成为一种有效的双氧还原催化剂。然而，为了达到足够的反应速率，需要制定使中间物质不稳定的策略。这是一个持续的挑战，因为与使用其他过渡金属的方法相比，人们对锰作为二氧还原催化剂的了解要少得多。这些研究工作将通过研究锰活性位点的初级环境如何调节双氧结合，如何控制底物向活性位点的转移以选择特定的还原产物，以及如何使用二次金属离子破坏稳定的锰双氧加合物以加速观察到的反应来解决这一需求。总的来说，这些关于锰基双氧还原的研究正在评估调节两种可能的反应产物：过氧化氢和水的反应途径的结构-功能参数。通过这种迭代设计策略提高锰基电催化剂的活性，这些研究正在解决对二氧还原的基本理解的持续需求，这是长期更好地利用可再生能源所必需的。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With the support of the Chemical Catalysis program in the Division of Chemistry, Charles W. Machan of the University of Virginia is studying the catalytic reduction of dioxygen by molecular manganese compounds. The reduction of dioxygen can be used for energy production from chemical bonds in devices such as fuel cells, where it is the preferred reaction to pair with the oxidation of chemical fuels to produce power. In order to make these systems deployable and scalable, it is essential to develop catalysts made from earth abundant materials. Although Mn is known to have strong interactions with dioxygen, catalysts made from this metal are relatively rare because effective strategies to accelerate catalysis based on Mn are underdeveloped. These studies on dioxygen reduction are aimed at developing design principles for better manganese catalysts, to achieve sufficient performance metrics to compete with other transition metals. An important part of these efforts is a research-focused educational outreach program to provide students with training in science communication. Kits will also be developed to provide research-based lab experience for undergraduates at all levels. The research goals under study and the educational components under development are addressing important priorities for society by meeting the growing needs for new energy technologies and familiarizing students with energy research at early career stages.Under this award, the Machan research team at the University of Virginia is studying the catalytic reduction of dioxygen by molecular manganese compounds. As an earth abundant transition metal that binds strongly to dioxygen, manganese has great potential to be an effective catalyst for dioxygen reduction. However, to achieve sufficient reaction rates, there is a need to develop strategies for destabilizing the intermediate species. This is an ongoing challenge, since far less is known about the use of manganese as a catalyst for dioxygen reduction than is known for approaches employing other transition metals. These research efforts will address this need by investigating how the primary environment of the manganese active site regulates dioxygen binding, how the transfer of substrate to the active site can be controlled to select for specific reduction products, and how the use of secondary metal ions can disrupt stable manganese dioxygen adducts to accelerate the observed reactions. Overall, these studies on manganese-based dioxygen reduction are evaluating the structure-function parameters that regulate the reaction pathways for the two possible reaction products: hydrogen peroxide and water. By improving the activity of manganese-based electrocatalysts through this iterative design strategy, these studies are addressing the ongoing need for the fundamental understanding of dioxygen reduction, which is required for better renewable energy utilization in the long term.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.