SusChEM: Rational Design and Synthesis of Stable Strain- and Defect-Rich Cu/Ceramic Nanocomposites for Efficient CO2 Reduction

非技术总结：在材料研究部陶瓷项目的支持下，Tewodros Asefa教授正在开发新型纳米颗粒，该纳米颗粒包含夹在两种金属氧化物之间的富含缺陷和应变的铜纳米晶体。这些材料正被用于研究纳米铜晶体将二氧化碳(一种温室气体)转化为甲醇(一种合成燃料和一种商品化学品)的稳定性和催化活性。尽管富含缺陷和应变的铜纳米晶对这种化学转化具有很高的催化活性，但不幸的是，这些位置也不稳定，因此很容易失去活性。这一问题可以通过纳米材料的设计来克服，纳米材料包括金属氧化物核心和围绕着应变和缺陷丰富的纳米晶的多孔金属氧化物外壳。这种独特的结构允许纳米晶体保留其催化超活性中心，同时保持稳定，并允许系统地研究高温下纳米铜晶体的结构和催化性能之间的相互作用(用于将二氧化碳转化为甲醇的条件)。美国国家标准与技术研究所(NIST)高分辨率中子散射中心(CHRNS)最先进的高分辨率中子散射技术正被用于破译纳米颗粒上的缺陷和应变，以及它们在催化过程中可能发生的任何变化。CHRNS的仪器设备允许对正在开发的材料的结构和动力学进行各种独特的表征。技术细节：虽然最近发现铜纳米晶上的缺陷和应变位置对二氧化碳高温化学转化为甲醇具有很高的催化活性，但不幸的是，这些位置在热力学上也不稳定，因此很容易在这些条件下进行烧结和失活。这项研究的主要特点是设计了包含稳定和高活性的、缺陷和应变丰富的核-壳纳米铜纳米晶，夹在金属氧化物核心和多孔金属氧化物外壳之间，并使用所产生的纳米催化剂来透彻地了解铜和其他相关金属纳米材料在高温催化条件下的结构-性能关系。这种铜纳米晶的合成是通过一种称为受控配体辅助刻蚀的方法进行的。这项研究最终揭示了需要在铜和其他相关金属纳米材料中定制的关键结构因素，以有效催化各种反应，包括将二氧化碳转化为甲醇，或将温室气体转化为合成燃料或商品化学品。此外，该项目还为一名研究生和三名或更多本科生提供培训，其中包括那些来自历史上在科学和工程领域代表性不足的群体的学生。参与这项研究的学生利用罗格斯表面改性实验室和NIST提供的基础设施，获得各种材料的跨学科实践培训，包括合成方法、催化和材料表征。此外，这项研究的结果将被纳入研究生课程，这些课程涉及可持续和可再生能源应用的材料工程。

NON-TECHNICAL SUMMARY: In this project, supported by the Ceramics Program in the Division of Materials Research, Professor Tewodros Asefa is developing novel nanoparticles containing defect- and strain-rich copper nanocrystals sandwiched between two metal oxides. These materials are being used to investigate the stability and catalytic activity of copper nanocrystals for the conversion of carbon dioxide (a greenhouse gas) to methanol (a synthetic fuel and a commodity chemical). While defect- and strain-rich copper nanocrystals have high catalytic activity for this chemical conversion, these very sites are also unfortunately unstable, and thus can easily lose their activity. This problem is overcome by the design of nanomaterials that comprise metal oxide cores and porous metal oxide shells around the strain- and defect-rich copper nanocrystals. This unique structure allows the nanocrystals to retain their catalytically super-active sites, while remaining stable and allowing for the systematic investigation of the interplay between the structures and catalytic properties of copper nanocrystals under high temperature (the condition used for converting carbon dioxide to methanol). State-of-the-art high-resolution neutron scattering techniques at the Center for High Resolution Neutron Scattering (CHRNS) in the National Institute of Standards and Technology (NIST) are being used to decipher the defects and strains on the nanoparticles and any changes that they may undergo during catalysis. The instrumentation at CHRNS allows for various unique characterizations of the structure and dynamics of the materials being developed. TECHNICAL DETAILS: While defect and strained sites on copper nanocrystals have been recently found to have high catalytic activity for high temperature chemical conversion of carbon dioxide to methanol, these very sites are also unfortunately thermodynamically unstable, and thus can easily undergo sintering and deactivation under these conditions. Key features of the research are the designing of core-shell nanoparticles containing stable and highly active, defect- and strain-rich copper nanocrystals sandwiched between metal oxide cores and porous metal oxide shells, and using the resulting nanocatalysts to provide a thorough understanding of the structure-property relationships of copper and other related metallic nanomaterials under high temperature catalytic conditions. The synthesis of such copper nanocrystals is carried out by a method called controlled ligand-assisted etching. The research ultimately uncovers key structural factors that need to be tailored in copper and other related metallic nanomaterials for the efficient catalysis of various reactions, including the conversion of carbon dioxide to methanol, or a greenhouse gas to a synthetic fuel or a commodity chemical. Additionally, the project provides training of a graduate student and three or more undergraduate students, including those from groups historically underrepresented in science and engineering. The students participating in this research gain interdisciplinary, hands-on training with a variety of materials synthetic methods, catalysis, and materials characterization using the infrastructure available at the Rutgers Laboratory for Surface Modification, as well as that available at NIST. Furthermore, the results from the research will be incorporated into graduate course offerings that address materials engineering for sustainable and renewable energy applications.