Shape-Dependent Nanocatalysis

技术概述：纳米粒子(NP)催化剂的工作状态可能不是催化剂制备时的状态，而是一种适应特定反应条件的结构和/或化学异构体。本项目研究金属NP催化剂的动力学性质及其对环境的响应。其智力优势是：(1)改进的合成方法的发展导致了独特的NP结构，可以用来更好地理解结构-反应关系；(2)适合于研究不同几何尺寸的纳米粒子的原位和非原位原子水平表征方法的进步。胶束包埋法将被用来制备高度均匀的金和铂纳米颗粒负载在二氧化钛(110)和伽马-氧化铝。以异丙醇的氧化反应为模型反应。原位和非原位X射线吸收光谱(XAS)、原子分辨扫描和环境透射电子显微镜(STEM，E-TEM)、X射线光电子能谱、扫描隧道显微镜和原子力显微镜将协同结合来表征模型纳米催化剂。非技术综述：现在人们都知道，金属纳米颗粒(NPs)与其块状纳米颗粒相比具有独特的性质，包括增强的化学反应活性。尽管纳米粒子催化的化学过程具有巨大的工业和环境相关性，但其催化性能提高的原因仍不清楚。这项研究计划的目的是加深对纳米粒子在工业反应条件下发生的变化以及粒子几何和结构，特别是形状对催化反应活性的影响的了解。这项研究的更广泛的影响涉及到现有催化剂的优化和未来催化剂的合理设计，通过深入了解负载型金属纳米催化剂的形状和反应活性之间的关系。此外，所选择的模型反应在能源生产(酒精燃料电池)和环境修复(去除挥发性有机化合物)领域具有广泛的应用。此外，该项目将支持一名博士、三名本科生(其中一名来自耶希瓦大学斯特恩女子学院)和一名K-12女学生的研究工作。参与该项目的学生将可以使用Brookaven NAT提供的用户设施。实验室。用于现场催化研究。此外，PI和共同PI将包括与本研究相关的基本概念，以及针对中学生和K-12学生的双语(英语-西班牙语)扩展网站上的在线培训模块。这项研究得到材料研究部固体和材料化学项目的支持。

TECHNICAL SUMMARY:The working state of nanoparticle (NP) catalysts might not be the state in which the catalysts were prepared, but a structural and/or chemical isomer that adapted to the particular reaction conditions. This project investigates the dynamic nature of metal NP catalysts and their response to their environment. The intellectual merits are: (1) the development of improved synthetic methods leading to unique NP structures that can be used to achieve a better understanding of structure-reactivity relationships; (2) the advancement of in-situ and ex-situ atomic-level characterization methods suitable for the study of nm-sized particles with variable geometries. Micelle encapsulation methods will be used to produce highly uniform Au and Pt NPs supported on TiO2(110) and gamma-Al2O3. The oxidation of 2-propanol will be used as model reaction. In-situ and ex-situ X-ray absorption spectroscopy (XAS), atomically resolved scanning and environmental transmission electron microscopy (STEM, E-TEM), X-ray photoelectron spectroscopy, scanning tunneling microscopy, and atomic force microscopy will be synergistically combined to characterize the model nanocatalysts. NON-TECHNICAL SUMMARY:It is now common knowledge that metal nanoparticles (NPs) possess unique properties as compared to their bulk counterparts, including enhanced chemical reactivities. Despite the enormous industrial and environmental relevance of chemical processes catalyzed by NPs, the origin of the improved catalytic performance is still not well understood. The objective of this research proposal is to improve the understanding of the changes that NPs undergo under industrial reaction conditions, as well as the effect of particle geometry and structure, in particular, shape, on catalytic reactivity. The broader impacts of this study relate to the optimization of existing catalysts and rational design of the future ones by gaining insight into the correlations between the shape and the reactivity of supported metal nanocatalysts. Further, the model reaction selected has broad applications in the fields of energy generation (alcohol fuel cells) and environmental remediation (removal of volatile organic compounds). In addition, this project will support the research efforts of one PhD, three undergraduates (one of them from Stern College for Women at Yeshiva Univ.), and a female K-12 student. The students involved in this project will have access to user facilities available at Brookhaven Nat. Lab. for in-situ catalysis research. Furthermore, the PI and co-PI will include basic concepts related to the present research and online training modules on a bilingual (English-Spanish) outreach website directed to middle-school and K-12 students.This research is supported by the Solid State and Materials Chemistry program in the Division of Materials Research.