CAS: Developing Homogeneous Mn Catalyst Systems for the Oxygen Reduction Reaction

CAS：开发用于氧还原反应的均相锰催化剂体系

• 批准号: 2102156
• 负责人: Charles Machan
• 金额: $ 47.5万
• 依托单位: University of Virginia Main Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-05-01 至 2025-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2102156&HistoricalAwards=false
• 关键词: CAS; Developing; Homogeneous; Mn; Catalyst

With the support of the Chemical Catalysis program in the Division of Chemistry, Dr. Charles W. Machan of the University of Virginia is studying the catalytic reduction of dioxygen by molecular manganese compounds. The reduction of dioxygen is important for producing energy from chemical bonds. Fuel cells, for example, often employ the reduction of dioxygen to water to generate clean energy. The current best catalysts for this reaction are based on platinum metal, which is rare and expensive. In the search for earth-abundant alternatives, systems containing iron and cobalt have been studied extensively, however, manganese versions of these systems are more poorly understood. Manganese generally interacts strongly with dioxygen and has the potential to rival or exceed the catalytic activity of iron or cobalt. These studies will achieve this by developing design principles for dioxygen reduction by manganese complexes, thus enabling optimized systems with improved performance. Integrated into these efforts is a research-focused educational outreach program, which will develop a scientific communication training program and a research-based lab experience. The integrated research and educational components will address fundamental challenges for the field and priorities of the current NSF Strategic Plan, with the goal of maximizing the health, environmental and economic benefits of renewable energy technologies.With the support of the Chemical Catalysis program in the Division of Chemistry, Dr. Charles W. Machan of the University of Virginia is studying the catalytic reduction of dioxygen by molecular manganese compounds. When paired with the oxidation of energy rich molecules, dioxygen reduction is a convenient way to drive oxidation reactions or to convert chemical energy to electrical energy. Manganese metal centers, while underrepresented as molecular catalyst active sites, have strong interactions with dioxygen and could demonstrate catalytic activity that rivals or exceeds the activity of more well-understood iron and cobalt species. A coordination chemistry-based approach will be used to enhance the binding and activation of dioxygen by tuning electronic properties at the Mn center, with the ultimate goal of improving catalytic performance. In initial studies, conditions for the selective generation of hydrogen peroxide or water as the reaction product have been developed: hydrogen peroxide is a valuable chemical oxidant and water is the desired half-reaction for fuel cells. Understanding how to achieve high selectivity and activity for each of these products has implications for renewable energy utilization. To address the ongoing need for fundamental understanding of the reduction of dioxygen by manganese complexes, the role of axial ligands in dioxygen binding and activation will be quantified, the catalytic response will be improved by synthetically modifying the ligand framework, and conditions for selective hydrogen peroxide and water production will be sought using redox mediators.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.

在化学系化学催化项目的支持下，弗吉尼亚大学的 Charles W. Machan 博士正在研究分子锰化合物催化还原双氧。分子氧的减少对于从化学键产生能量很重要。例如，燃料电池经常利用将分子氧还原成水来产生清洁能源。目前该反应最好的催化剂是铂金属，这种催化剂稀有且昂贵。在寻找地球上丰富的替代品的过程中，人们对含有铁和钴的系统进行了广泛的研究，然而，人们对这些系统的锰版本却知之甚少。锰通常与双氧发生强烈相互作用，并且有可能与铁或钴的催化活性相媲美或超过。这些研究将通过开发锰络合物还原双氧的设计原理来实现这一目标，从而实现具有改进性能的优化系统。这些努力中融入了一项以研究为重点的教育推广计划，该计划将开发科学传播培训计划和基于研究的实验室经验。综合研究和教育部分将解决当前 NSF 战略计划领域和优先事项的基本挑战，目标是最大限度地提高可再生能源技术的健康、环境和经济效益。在该部门化学催化计划的支持下弗吉尼亚大学化学系的 Charles W. Machan 博士正在研究分子锰化合物催化还原双氧。当与富含能量的分子的氧化结合时，分子氧还原是驱动氧化反应或将化学能转化为电能的便捷方法。锰金属中心虽然作为分子催化剂活性位点的代表性不足，但与双氧具有很强的相互作用，并且可以表现出与更广为人知的铁和钴物种的活性相媲美或超过的催化活性。基于配位化学的方法将用于通过调整锰中心的电子特性来增强分子氧的结合和活化，最终目标是提高催化性能。在初步研究中，已经开发出了选择性生成过氧化氢或水作为反应产物的条件：过氧化氢是一种有价值的化学氧化剂，而水是燃料电池所需的半反应。了解如何实现这些产品的高选择性和活性对于可再生能源的利用具有重要意义。为了满足对锰络合物还原分子氧的基本理解的持续需求，将量化轴向配体在分子氧结合和活化中的作用，通过合成修饰配体框架和选择性过氧化氢的条件来改善催化响应该奖项反映了 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。

项目成果

Pendent Relay Enhances H 2 O 2 Selectivity during Dioxygen Reduction Mediated by Bipyridine-Based Co–N 2 O 2 Complexes

悬垂继电器增强联吡啶基 Co-N 2 O 2 配合物介导的双氧还原过程中 H 2 O 2 的选择性

• DOI: 10.1021/jacs.1c03381
• 发表时间: 2021-08-25
• 期刊: Journal of the American Chemical Society
• 影响因子: 15
• 作者: Nichols, Asa W.;Cook, Emma N.;Gan, Yunqiao J.;Miedaner, Peter R.;Dressel, Julia M.;Dickie, Diane A.;Shafaat, Hannah S.;Machan, Charles W.
• 通讯作者: Machan, Charles W.

Metal-Free Homogeneous O 2 Reduction by an Iminium-Based Electrocatalyst

亚胺基电催化剂实现无金属均相 O 2 还原

• DOI: 10.1021/jacs.3c14549
• 发表时间: 2024-03
• 期刊: Journal of the American Chemical Society
• 影响因子: 15
• 作者: Cook, Emma N.;Davis, Anna E.;Hilinski, Michael K.;Machan, Charles W.
• 通讯作者: Machan, Charles W.

Redox Mediators in Homogeneous Co-electrocatalysis

均相共电催化中的氧化还原介体

• DOI: 10.1021/jacs.2c10033
• 发表时间: 2023-02
• 期刊: Journal of the American Chemical Society
• 影响因子: 15
• 作者: Reid, Amelia G.;Machan, Charles W.
• 通讯作者: Machan, Charles W.

Catalytic Reduction of Dioxygen to Water by a Bioinspired Non-Heme Iron Complex via a 2+2 Mechanism

仿生非血红素铁络合物通过 2 2 机制将分子氧催化还原为水

• DOI: 10.1021/jacs.1c04572
• 发表时间: 2021-10
• 期刊: Journal of the American Chemical Society
• 影响因子: 15
• 作者: Cook, Emma N.;Dickie, Diane A.;Machan, Charles W.
• 通讯作者: Machan, Charles W.

Homogeneous catalysis of dioxygen reduction by molecular Mn complexes

分子锰配合物均相催化双氧还原

• DOI: 10.1039/d2cc04628h
• 发表时间: 2022-10
• 期刊: Chemical Communications
• 影响因子: 4.9
• 作者: Cook, Emma N.;Machan, Charles W.
• 通讯作者: Machan, Charles W.