Increasing the Reductive Stability of Self-Assembled Monolayers on Metallic Surfaces to Enable Reductive Electrocatalysis

提高金属表面自组装单分子层的还原稳定性以实现还原电催化

• 批准号: 2004035
• 负责人: Charles McCrory
• 金额: $ 48万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2004035&HistoricalAwards=false
• 关键词: Increasing; Reductive; Stability; Self; Assembled

Professors Charles McCrory and James Penner-Hahn of the University of Michigan-Ann Arbor are supported by the Macromolecular, Supramolecular, and Nanochemistry Program of the NSF Division of Chemistry to study the sequence of events (mechanisms) that cause single layer films of organic molecules on solid surfaces (self-assembled monolayers, or SAMs) to detach from the surface under electrochemical operating conditions. The process, which is called reductive desorption, is poorly understood. A better understanding of the process paves the way for the design of more robust SAM systems. A combination of electroanalytical techniques, advanced X-ray and IR spectroscopies are used to provide insight into the mechanism of desorption. Robust SAMs are critical for many practical applications, including their use to anchor catalysts for reactions relevant to energy and environmental chemistry, such as carbon dioxide reduction for solar fuels generation and nitrate reduction for wastewater remediation. This project also provides a platform to promote scientific literacy through formal training of student researchers in communicating to the general public, active engagement with the local community through interactive demonstrations of the concepts of catalysis and corrosion, and hosting Detroit high school students in summer research internships at the University of Michigan.The use of well-defined self-assembled monolayers (SAMs) to tether molecular catalysts to electrode surfaces facilitates the careful mechanistic, kinetic, and spectroelectrochemical studies needed for new catalyst development. However, the use of SAMs for tethering electrocatalysts to electrode surfaces for reactions of societal importance, such as carbon dioxide reduction and nitrate reduction, is limited by the reductive instability of thiol-based SAMs on gold and other metal surfaces. The discovery of reductively-stable SAMs for the direct immobilization of molecular catalysts to metallic surfaces is an enabling technology in molecular electrocatalysis that may facilitate careful and complete mechanistic and kinetic analysis of known and emerging electrocatalysts. Currently, a lack of mechanistic understanding of the reductive desorption process limits the rational design of new, more-reductively stable systems. This project uses a combination of electroanalytical techniques and advanced X-ray and infrared spectroscopies to probe the electronic and physical structures of self-assembled monolayers during the reductive desorption process, providing insights into the mechanism of reductive desorption. The results of these mechanistic studies may facilitate the rational design of new, more reductively-stable SAMs that enable the immobilization and in situ spectroelectrochemical study of electrocatalysts for multi-electron transformations important to energy and environmental chemistry.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.

密歇根大学安娜堡分校的Charles McCrory和James Penner-Hahn教授得到了美国国家科学基金会化学部大分子、超分子和纳米化学项目的支持，研究了在电化学操作条件下导致固体表面有机分子单层膜（自组装单层膜，或称SAMs）从表面分离的事件序列（机制）。这一过程被称为还原性脱附，人们对其了解甚少。更好地理解该过程为设计更健壮的SAM系统铺平了道路。结合电分析技术，先进的x射线和红外光谱被用来提供深入了解解吸机制。强大的sam对于许多实际应用至关重要，包括它们在与能源和环境化学相关的反应中用作锚定催化剂，例如用于太阳能燃料生产的二氧化碳还原和用于废水修复的硝酸盐还原。该项目还提供了一个平台，通过正式培训学生研究人员与公众交流，通过互动展示催化和腐蚀概念，积极参与当地社区，并邀请底特律高中生在密歇根大学进行暑期研究实习，从而提高科学素养。使用定义良好的自组装单层（SAMs）将分子催化剂拴在电极表面，有助于进行新催化剂开发所需的细致的机理、动力学和光谱电化学研究。然而，由于硫醇基SAMs在黄金和其他金属表面的还原不稳定性，将电催化剂拴在电极表面以进行具有社会意义的反应（如二氧化碳还原和硝酸盐还原）的使用受到了限制。还原稳定的SAMs的发现，直接将分子催化剂固定在金属表面，是分子电催化的一项使能技术，可以促进对已知和新兴电催化剂的仔细和完整的机理和动力学分析。目前，缺乏对还原性脱附过程的机理理解，限制了新的、还原性更稳定的系统的合理设计。本项目将电分析技术与先进的x射线和红外光谱相结合，探测自组装单层在还原脱附过程中的电子和物理结构，为还原脱附机理提供见解。这些机理研究的结果可能有助于合理设计新的，更还原稳定的sam，从而实现对能源和环境化学重要的多电子转化电催化剂的固定化和原位光谱电化学研究。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。