NSF-DFG EChem: CAS: Mechanistic Interrogation of Electrocatalytic Hydrogen Evolution by an Artificial Hydrogenase

在美国国家科学基金会化学部的支持下，俄亥俄州立大学的Hannah Shafaat和慕尼黑工业大学和马克斯普朗克化学能转换研究所的合作者将开发和表征从水中生产氢气的优化催化系统。开发能够有效地将电化学能量转化为可持续燃料（如H2）的催化剂是用环境友好型替代品取代化石燃料必须克服的一个关键障碍。自然界中氢转化的催化剂——被称为氢化酶的酶，表现出无与伦比的活性；尽管全球都在努力，但目前还没有开发出在速度和效率上可与天然氢化酶相媲美的可持续合成催化剂。虽然自然系统的实际应用是有限的，但几十年来对氢化酶的研究已经提供了对酶性质和催化机制的实质性理解，揭示了功能所必需的关键特征。这些一般的设计原则将应用于构建一个高效的电化学能量转换催化系统。通过这个项目，来自三个团队的研究生将结合他们在生物化学、无机化学、光谱学和电化学等领域的专业知识，建立跨学科的国际合作。从这些基础研究中获得的见解有望广泛应用于可扩展的电化学储能材料的产生，包括水氧化、固氮和二氧化碳减排，具有潜在的全球社会经济影响。进行研究的学生和博士后学者将进行国际交流，包括一个涉及整个项目团队的研讨会。这种催化剂设计方法来自俄亥俄州立大学的Hannah Shafaat和她的德国合作者，他们专注于开发一种强大的人工氢化酶电催化剂。利用金属酶模型作为明确定义的支架，该团队将结合选择的分子复合物作为分子内电子继电器，对天然氧化还原活性辅助因子进行功能建模，并确定它们在电催化中的作用。混合酶将被固定在电极表面，被设计成电子转移伙伴，影响界面电荷转移的系统变量将被探测。研究计划的具体目标是：(i)设计和实施整合各个组成部分的策略；（ii）应用新的原位光谱电化学研究，通过混合结构来询问H2的演化机制；（iii）通过调整二级和外球性质来优化这些系统，以提高催化效率。通过确定每个组分在催化中所起的作用，可以改进缓慢的步骤，消除非生产性或降解途径，从而系统地改进催化系统。这项研究是由NSF- dfg牵头机构在电合成和电催化活动（NSF- dfg化学）机会NSF 20-578资助的。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 support from the NSF Division of Chemistry, Hannah Shafaat of Ohio State University and collaborators at the Technical University of Munich and the Max Planck Institute for Chemical Energy Conversion will develop and characterize optimized catalytic systems for production of hydrogen gas from water. The development of catalysts that can efficiently convert electrochemical energy into sustainable fuels such as H2 represents a critical obstacle that must be overcome in order to replace fossil fuels with environmentally friendly alternatives. Nature’s catalysts for hydrogen conversion, enzymes known as hydrogenases, exhibit an unparalleled degree of activity; despite global efforts, no sustainable synthetic catalyst has yet been developed that is comparable in rate and efficiency to the natural hydrogenases. While practical application of the natural systems is limited, decades of study on hydrogenases have provided substantial understanding of the enzyme properties as well as the catalytic mechanism, revealing key features that are necessary for function. These general design principles will be applied to construct a highly efficient catalytic system for electrochemical energy conversion. Through this project, graduate students from all three teams will combine their expertise across areas of biochemistry, inorganic chemistry, spectroscopy, and electrochemistry, building interdisciplinary international collaborations. The insight obtained from these fundamental studies is expected to be broadly applicable to the generation of scalable materials for electrochemical energy storage, including water oxidation, nitrogen fixation, and CO2 reduction, with potential for global socioeconomic impact. Students and postdoctoral scholars conducting the research will experience international exchange, including a workshop involving the entire project team.This approach to catalyst design from the group of Hannah Shafaat at Ohio State University and her German collaborators focuses on the development of a robust, artificial hydrogenase electrocatalyst. Using a model metalloenzyme as a well-defined scaffold, the team will incorporate select molecular complexes as intramolecular electron relays to functionally model the native redox-active cofactors and establish their roles in electrocatalysis. The hybrid enzyme will be anchored onto an electrode surface, designed to act as an electron transfer partner, and system variables that impact interfacial charge transfer will be probed. The specific objectives of the research program are to (i) design and implement strategies for integration of the individual components; (ii) to apply novel in situ spectro-electrochemical studies to interrogate the mechanism of H2 evolution by the hybrid constructs and (iii) to optimize these systems by tuning secondary and outer sphere properties to enhance catalytic efficiencies. By identifying the role that each component plays in catalysis, sluggish steps will be improved upon and unproductive or degradative pathways can be eradicated to systematically improve the catalytic system.This research was funded under the NSF-DFG Lead Agency Activity in Electrosynthesis and Electrocatalysis (NSF-DFG EChem) opportunity NSF 20-578.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.