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，弗吉尼亚大学的查尔斯·W·马坎正在研究分子锰化合物对二氧化氧的催化还原。氧气的还原可用于燃料电池等设备中的化学键产生能量，在这些设备中，它是与化学燃料的氧化配对产生电力的首选反应。为了使这些系统可部署和可扩展，开发由地球上丰富的材料制成的催化剂是必不可少的。虽然众所周知，锰与氧气有很强的相互作用，但由这种金属制成的催化剂相对较少，因为基于锰的有效催化策略还没有开发出来。这些关于氧气还原的研究旨在开发更好的锰催化剂的设计原则，以获得足够的性能指标来与其他过渡金属竞争。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，为各级本科生提供研究型实验室体验。正在研究的研究目标和正在开发的教育组成部分正在解决社会的重要优先事项，通过满足对新能源技术日益增长的需求，并在职业生涯的早期阶段让学生熟悉能源研究。在这个奖项下，弗吉尼亚大学的马坎研究小组正在研究分子锰化合物对氧气的催化还原。锰是一种富含稀土的过渡金属，与氧气结合强烈，具有很大的潜力成为氧气还原的有效催化剂。然而，为了达到足够的反应速度，需要制定策略来破坏中间物种的稳定。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，人们对使用锰作为二氧化碳还原催化剂的了解要少得多。这些研究工作将通过调查锰活性中心的初级环境如何调节二氧化氧结合，如何控制底物到活性中心的转移以选择特定的还原产物，以及使用二次金属离子如何扰乱稳定的二氧化锰加合物以加速观察到的反应来满足这一需求。总体而言，这些关于锰基氧气还原的研究正在评估结构-功能参数，这些参数调节了两种可能的反应产物：过氧化氢和水的反应路径。通过这种迭代设计策略提高锰基催化剂的活性，这些研究正在解决对氧气还原的基本了解的持续需求，这是更好地长期利用可再生能源所必需的。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。

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.