Shape-Dependent Nanocatalysis

技术概述：纳米颗粒（NP）催化剂的工作状态可能不是催化剂制备时的状态，而是适应特定反应条件的结构和/或化学异构体。本项目研究了金属NP催化剂的动态性质及其对环境的响应。智力上的优点是：(1)改进的合成方法的发展导致独特的NP结构，可用于更好地理解结构-反应性关系；(2)原位和非原位原子级表征方法的进展，适用于纳米级可变几何颗粒的研究。胶束封装方法将用于制备高度均匀的负载在TiO2（110）和γ - al2o3上的Au和Pt纳米粒子。以2-丙醇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。非技术总结：现在大家都知道，金属纳米颗粒（NPs）与它们的体积对应物相比具有独特的性质，包括增强的化学反应性。尽管由NPs催化的化学过程具有巨大的工业和环境相关性，但催化性能改善的起源仍然没有得到很好的理解。本研究计划的目的是提高对NPs在工业反应条件下所经历的变化的理解，以及颗粒几何形状和结构，特别是形状对催化反应性的影响。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，通过深入了解负载金属纳米催化剂的形状和反应性之间的相关性。此外，所选择的模型反应在能源产生（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（其中一人来自叶史瓦大学斯特恩女子学院）和一名K-12女学生的研究工作。参与这个项目的学生将有机会使用布鲁克海文Nat实验室提供的用户设施。用于原位催化研究。此外，PI和共同PI将包括与当前研究有关的基本概念，以及面向中学和K-12学生的双语（英语-西班牙语）外联网站上的在线培训模块。本研究得到了材料研究部固态与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.