Atomically Dispersed Metal Catalysts for Electrochemical Hydrogen Evolution

加州大学圣克鲁兹分校的Shaowei Chen教授得到了化学系化学催化计划的支持，研究使用嵌入碳基质中的单个金属原子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，并提供与支撑碳基底的最大相互作用。 这提供了一种选择，用于有意地操纵金属原子的电子性质，并因此操纵催化剂的电催化活性。 析氢反应是水电解中产生氢的关键过程，氢是一种清洁和可持续的能源。 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旨在扩大妇女、大学生和高中生参与科学研究的若干外联活动相结合。 本项目的目标是开发有效的策略来制备用于碱性介质中的析氢反应（HER）的高性能单原子催化剂（SAC）。HER是电化学水分解产生氢的关键过程，氢是一种清洁和可持续的能源。该项目的主要动机是最近在主要研究者的实验室中取得的突破，其中发现嵌入氮掺杂碳的钌单原子催化剂在碱性HER中的性能甚至超过铂。为了进一步提高电催化活性，拟议的研究将集中在以下任务上：（i）通过催化剂的热工程使钌SAC浓度最大化;（ii）用其他金属如铱、铑和钯制备SAC;以及（iii）制备初始集中于钌和金的双金属SAC。 一套分析表面技术用于表征催化材料。 并行进行基于密度泛函理论计算的理论建模和模拟，其中结构模型与实验数据相关，以便解开负责HER电催化活性的原子位点，并有助于催化剂设计、结构工程和最终的催化剂优化。 预计该项目的成果可能会促进有效的SAC的合理设计和工程，竞争对手的商业铂/碳catalysts.This奖项反映了NSF的法定使命，并已被认为是值得的支持，通过评估使用基金会的知识价值和更广泛的影响审查标准。

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.