Atomically Dispersed Metal Catalysts for Electrochemical Hydrogen Evolution

加州大学圣克鲁兹分校的陈少伟教授在化学系化学催化项目的支持下，研究将单个金属原子嵌入碳基体中，作为工业上重要的析氢反应的新催化材料。在原子尺度上嵌入金属代表了催化材料的充分利用，并提供了与支撑碳衬底最大的相互作用。这为有意操纵金属原子的电子性质和催化剂的电催化活性提供了一种选择。析氢反应是水电解制氢的关键过程，是一种清洁、可持续的能源。铂基纳米颗粒已被广泛用作该反应的催化剂。然而，铂的高成本和有限的自然储量极大地阻碍了这种电化学技术的广泛应用。因此，开发低成本、高性能的可行的替代电催化剂具有重要的基础和技术意义。该项目为学生提供了在可再生能源研究的跨学科研究环境中接受培训的机会。与项目有关的教育材料与若干旨在扩大妇女、本科生和高中生参与科学研究的外联活动结合在一起。本项目的目的是为碱性介质中析氢反应（HER）制备高性能单原子催化剂（SACs）制定有效的策略。HER是电化学水分解生成氢这一清洁可持续能源的关键过程。该项目的主要动机是由首席研究员实验室最近的一项突破，其中发现嵌入氮掺杂碳中的钌单原子催化剂在碱性HER中的表现甚至优于铂。为了进一步提高催化剂的电催化活性，今后的研究工作将主要集中在以下几个方面：(1)通过催化剂的热工技术使钌SAC浓度最大化；（ii）用其他金属如铱、铑和钯制备sac；（iii）制备双金属SACs，最初的重点是钌和金。一套分析表面技术被用来表征催化材料。基于密度泛函理论计算的理论建模和模拟与实验数据相关的结构模型并行进行，以揭示负责HER电催化活性的原子位点，并有助于催化剂设计，结构工程，最终优化催化剂。预计该项目的成果可能有助于合理设计和制造可与商业铂/碳催化剂相媲美的有效sac。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。

Professor Shaowei Chen of the University of California-Santa Cruz is supported by the Chemical Catalysis Program of the Division of Chemistry to investigate the use of individual metal atoms embedded within a carbon matrix as a new catalytic material for the industrially important hydrogen evolution reaction. Embedding metal on the atomic scale represents full utilization of the catalytic material and affords maximal interactions with the supporting carbon substrate. This provides an option for deliberate manipulation of the electronic properties of the metal atoms and hence the electrocatalytic activity of the catalyst. The hydrogen evolution reaction is a critical process in water electrolysis for the generation of hydrogen, a clean and sustainable energy source. Platinum-based nanoparticles have been used extensively as the catalysts of choice for this reaction. Yet the high costs and limited natural reserves of platinum have greatly hampered the wide-spread application of such electrochemical technologies. Thus, it is of both fundamental and technological significance to develop viable alternative electrocatalysts that are of low-cost and high-performance. The project offers an opportunity for students to be trained in an interdisciplinary research environment in renewable energy research. Project-related educational material is integrated with several outreach activities geared towards broadening participation of women, undergraduate and high school students in scientific research. The goal of this project is to develop effective strategies for the preparation of high-performance single atom catalysts (SACs) for the hydrogen evolution reaction (HER) in alkaline media. HER is a critical process in electrochemical water splitting to generate hydrogen, a clean and sustainable energy source. The project is primarily motivated by a recent breakthrough in the laboratory of the principle investigator, where ruthenium single atom catalysts embedded within nitrogen-doped carbon are found to even outperform platinum in alkaline HER. To further enhance the electrocatalytic activity, the proposed research will focus on the following tasks: (i) maximization of Ruthenium SAC concentration by thermal engineering of the catalysts; (ii) preparation of SACs with other metals, such as Iridium, Rhodium, and Palladium; and (iii) preparation of bimetallic SACs with the initial focus on Ruthenium and Gold. A suite of analytical surface techniques is used to characterize the catalytic materials. Theoretical modeling and simulations based on density functional theory calculations with structural models relevant to experimental data are carried out in parallel so as to unravel the atomic sites that are responsible for the HER electrocatalytic activity and aid in catalyst design, structural engineering, and ultimately, catalyst optimization. It is anticipated that the project outcome may facilitate the rational design and engineering of effective SACs that rival commercial platinum/carbon catalysts.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.