Collaborative Research: Directly probing the local coordination, charge state and stability of single atom catalysts – Critical insights from advanced TEM for promoting stability

合作研究：直接探测单原子催化剂的局域配位、电荷状态和稳定性 — 来自先进 TEM 的关键见解，以促进稳定性

• 批准号: 2031494
• 负责人: Xiaoqing Pan
• 金额: $ 53.14万
• 依托单位: University of California-Irvine
• 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: 2020-11-15 至 2024-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2031494&HistoricalAwards=false
• 关键词: Collaborative; Research; Directly; probing; local

The drive for atom-efficient catalysts with carefully controlled properties has motivated the development of single atom catalysts (SACs), where single precious metal atoms are stabilized on high-surface-area supports. SACs exhibit unique and potentially useful characteristics for chemical processes ranging from automotive catalysis to electrocatalysis. However, information about the structure of the metal binding site on the support and its stability under reaction conditions is sparse. This is due to a lack of insights into the uniformity of metal species and their mobility, which are challenging to assess from sample-averaged measurements. The investigators will overcome these limitations to obtain atomic-scale and quantitative insights into the working state of SACs by coupling state-of-the-art atomic resolution transmission electron microscopy and spectroscopy with careful catalyst synthesis and sample averaged analyses. The study will focus on the design of catalysts that utilize expensive and scarce noble metals more effectively, thus opening the door to more efficient and economical chemical manufacturing and environmental remediation technologies. The research is integrated with education and outreach activities to attract diverse junior scientists, including women and underrepresented minority groups, and train future leaders to address critical societal challenges.The project leverages unique electron microscopy facilities at the University of California-Irvine (UCI) with state-of-the-art catalyst synthesis and spectroscopic characterization capabilities at the University of California-Santa Barbara (UCSB). The central objectives of the research are to utilize advanced ex situ and in situ aberration-corrected scanning transmission electron microscopy and associated electron energy loss spectroscopy to probe the local coordination, metal charge state, and stability of SACs and correlate these properties to spectroscopic analysis by in situ infrared spectroscopy. The study of SACs benefits significantly from in situ sub-angstrom resolution imaging, as this provides site-specific information needed to interpret spectroscopic data from sample averaged measurements. This project focuses on Pt, Rh, and Au SACs on alumina (modified by atomically-dispersed Re and W), titania, and ceria which present variations in metal oxidation-state, support-reducibility, and available bindings sites. Detailed characterization of these systems enables the design of new catalysts with tuned reactivity and stability for catalytic processes such as CO oxidation, NO reduction, and alkene hydroformylation. The integration of the research with education and training of students allows the results from this project to be disseminated to the diverse student populations of UCI and UCSB during coursework and internships for undergraduate students, as well as to high school students from diverse backgrounds through summer school programs, which will promote their interest in scientific research and education.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.

对具有严格控制性能的原子高效催化剂的追求推动了单原子催化剂（SACs）的发展，其中单个贵金属原子稳定在高表面积载体上。sac在从汽车催化到电催化的化学过程中表现出独特和潜在的有用特性。然而，关于支架上金属结合位点的结构及其在反应条件下的稳定性的信息很少。这是由于缺乏对金属物种的均匀性及其流动性的了解，这很难从样本平均测量中进行评估。研究人员将克服这些限制，通过将最先进的原子分辨率透射电子显微镜和光谱学与仔细的催化剂合成和样品平均分析相结合，获得SACs工作状态的原子尺度和定量见解。这项研究将侧重于设计更有效地利用昂贵和稀有贵金属的催化剂，从而为更有效和经济的化学制造和环境修复技术打开大门。这项研究与教育和推广活动相结合，以吸引不同的青年科学家，包括妇女和代表性不足的少数群体，并培养未来的领导人来应对关键的社会挑战。该项目利用了加州大学欧文分校（UCI）独特的电子显微镜设备，以及加州大学圣巴巴拉分校（UCSB）最先进的催化剂合成和光谱表征能力。本研究的中心目标是利用先进的非原位和原位像差校正扫描透射电子显微镜和相关的电子能量损失光谱来探测SACs的局部配位，金属电荷状态和稳定性，并将这些特性与原位红外光谱分析相关联。SACs的研究从亚埃分辨率成像中获益良多，因为这提供了解释样品平均测量的光谱数据所需的特定地点信息。本项目重点研究氧化铝（由原子分散的Re和W修饰）、二氧化钛和二氧化铈上的Pt、Rh和Au SACs，这些SACs在金属氧化态、支持还原性和可用结合位点方面存在变化。这些系统的详细表征使得新的催化剂的设计具有调整反应性和稳定性的催化过程，如CO氧化，NO还原，烯烃氢甲酰化。将研究与教育和学生培训相结合，使该项目的成果能够在本科学生的课程和实习期间传播给UCI和UCSB的不同学生群体，并通过暑期学校项目传播给不同背景的高中生，从而提高他们对科学研究和教育的兴趣。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。

项目成果

Effect of Phosphorus Modulation in Iron Single‐Atom Catalysts for Peroxidase Mimicking

铁单原子催化剂中磷调节对模拟过氧化物酶的影响

• DOI: 10.1002/adma.202209633
• 发表时间: 2023
• 期刊: Advanced Materials
• 影响因子: 29.4
• 作者: Ding, Shichao;Barr, Jordan Alysia;Lyu, Zhaoyuan;Zhang, Fangyu;Wang, Maoyu;Tieu, Peter;Li, Xin;Engelhard, Mark H.;Feng, Zhenxing;Beckman, Scott P.
• 通讯作者: Beckman, Scott P.

Bifunctional hydroformylation on heterogeneous Rh-WOx pair site catalysts

• DOI: 10.1038/s41586-022-05075-4
• 发表时间: 2022-09-08
• 期刊: NATURE
• 影响因子: 64.8
• 作者: Ro, Insoo;Qi, Ji;Christopher, Phillip
• 通讯作者: Christopher, Phillip