NSF-DFG Echem: CAS: Cooperativity Between Immobilized Redox Mediators for Selective Anodic Biomass Valorization

NSF-DFG Echem：CAS：固定化氧化还原介体之间的协同作用，用于选择性阳极生物质增值

• 批准号: 2055689
• 负责人: Adam Holewinski
• 金额: $ 44.82万
• 依托单位: University of Colorado at Boulder
• 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: 2021-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2055689&HistoricalAwards=false
• 关键词: NSF; DFG; Echem; CAS; Cooperativity

With the support of the Chemical Catalysis program in the Division of Chemistry, Adam Holewinski and Wei Zhang of the University of Colorado-Boulder are studying new designs for catalytic materials. The project also involves collaborators from Rostock University in Germany. Electrocatalysts facilitate the interconversion of electrical energy and chemical bonds. These transformations are increasingly of interest for storage and extraction of renewable electricity via chemical fuels, as well as for synthesizing high volume chemical products that rely on large energy inputs. Efficient catalysts such as the enzymes found in nature often rely on cooperative interactions among multiple chemical functional groups to steer a reaction toward desired products. This project is focused on designing cooperative electrocatalysts where two species work together to drive a reaction with less electrical input than would be required from either species alone. Work will center on synthesizing catalysts where each mediator is attached to a polymer such that they remain in close proximity. While the knowledge to be gained is fundamentally applicable for a wide range of important chemistries, the project will progress from model reactions (e.g. selective oxidation of simple alcohols to aldehydes) to reactions involving higher value substrates. In particular, production of environmentally friendly monomer compounds for green plastics will be targeted using raw materials derived from biomass. From an applied perspective, the development of scalable oxidative processes could alter the economic landscape of electrolysis for chemical production. Educational integration initiatives will include inclusion of diverse undergraduates in the research process and continued development of web-based educational modules. International collaboration with Rostock University in Germany is a key component of the project and participating graduate students will have the opportunity for visiting research. The project was awarded through the "NSF-DFG Lead Agency Activity in Electrosynthesis and Electrocatalysis (NSF-DFG EChem)" opportunity, a collaborative solicitation that involves NSF and Deutsche Forschungsgemeinschaft (DFG).Under this collaborative research award, Adam Holewinski and Wei Zhang of the University of Colorado-Boulder will study new designs for catalytic materials. Designing tailored substrate binding environments with multiple participant functional groups is difficult to achieve with homogeneous molecular catalysts, and even more challenging using heterogeneous catalyst materials. This proposal aims to understand and develop cooperative electrocatalytic sites, comprised of an organic redox mediator and redox-active metal center, both performing electron transfer. The work draws on recent demonstrations of homogeneous redox mediator mechanisms in which a two-electron oxidation is achieved by extraction of one electron into each of two mediators, lowering the necessary applied potentials by avoiding higher mediator oxidation states, normally accessed to achieve two electron oxidation. The mechanism is fundamentally distinct from more common examples of cooperativity, such as metal-ligand. The collaborative research team seeks to develop the fundamental understanding and methodologies needed to effectively immobilize such cooperative catalysts onto (a) soluble (but easily separated) polymers and (b) heterogeneous electrodes. These two platforms provide complementary means to identify constraints imposed by immobilization and understand how best to retain cooperativity. Mechanistic studies will be used to understand electro-oxidation cooperativity in probe reactions of variable complexity: (i) selective conversion of primary alcohols to aldehydes; (ii) oxidation of 5-(hydroxymethyl)-furfural (HMF) to diformylfuran (DFF) (a monomer for green plastics along with other chemical applications), and (iii) multi-electron oxidation to generate carboxylic acids—particularly HMF to 2,5-furandicarboxylic acid (FDCA), another monomer requiring both aldehyde and alcohol group oxidation. These reactions are critical to the expanding field of biomass valorization and simultaneously serve as an informative testbed for understanding the key constraints to realize cooperativity. The work further addresses widespread issues related to benchmarking of electrocatalytic activity on complex materials, aiming to establish rigorous precedents for activity characterization.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.

在化学催化计划的支持下，科罗拉多 - 博尔德大学的亚当·霍尔温斯基和魏张正在研究催化材料的新设计。该项目还涉及德国罗斯托克大学的合作者。电催化剂促进电能和化学键的相互转换。对于通过化学燃料以及依赖大型能源输入的大量化学产品的合成，这些转换越来越引起人们对可再生电力的储存和提取。在自然界中发现的酶等有效的催化剂通常依赖于多个化学官能团之间的合作相互作用来引导对所需产品的反应。该项目的重点是设计合作的电催化剂，其中两个物种共同驱动反应，而反应比单独的任何一个物种所需的电源少。工作将集中于合成催化剂，每个介体都附着在聚合物上，以使它们保持近距离。尽管要获得的知识从根本上适用于广泛的重要化学分配，但该项目将从模型反应（例如，将简单醇的选择性氧化为醛）到涉及较高价值底物的反应进行进展。特别是，使用来自生物质的原材料来生产绿色塑料的环保单体化合物。从应用的角度来看，可扩展的氧化物过程的发展可能会改变电解的经济景观以用于化学生产。教育融合计划将包括将潜水员的本科生纳入研究过程，并持续开发基于网络的教育模块。与德国的罗斯托克大学（Rostock University）的国际合作是该项目的关键组成部分，参与研究生将有机会参观研究。该项目是通过“ NSF-DFG牵头代理机构在电气合成和电催化领域的活动（NSF-DFG Echem）”的机会，这是一种合作的招标，涉及NSF和Deutsche Forschungsgemeinschaft（DFG）。催化材料。使用均匀的分子催化剂来设计具有多个参与者官能团的量身定制的底物结合环境，并且使用异质催化剂材料进行了更大的挑战。该建议旨在理解和开发由有机氧化还原介体和氧化还原活性金属中心组成的合作电催化位点，均进行电子传输。这项工作借鉴了近期均质氧化还原介体机制的证明，其中通过将一个电子提取到两个介体中的每一个中来实现两电子氧化物，从而通过避免使用较高的介体氧化态来降低必要的施加电位，通常可以访问以实现两种电子氧化。该机制从根本上与更常见的协调实例不同，例如金属配体。协作研究团队旨在发展有效固定的协调催化剂所需的基本理解和方法，并将其固定在（a）固体（但易于分离）聚合物和（b）异构电极上。这两个平台提供了完整的含义，以确定固定化施加的约束，并了解如何最好地保留协调。机械研究将用于理解可变复杂性探针反应中的电氧化协调：（i）将初级醇的选择性转化为醛； (ii) oxidation of 5-(hydroxymethyl)-furfural (HMF) to diformylfuran (DFF) (a monomer for green plastics along with other chemical applications), and (iii) multi-electron oxide to generate carboxylic acids—particularly HMF to 2,5-furandicarbonylic acid (FDCA), another month requiring both aldehyde and酒精组氧化。这些反应对于扩大的生物质价值领域至关重要，仅作为了解实现协调的关键限制的信息性测试。这项工作进一步解决了与复杂材料上电催化活动基准测试有关的宽度问题，旨在为活动表征建立严格的先例。该奖项反映了NSF的法定任务，并被认为是通过基金会的知识分子优点评估来获得支持的支持，并具有更广泛的影响标准。