Defect Chemistry of Metal Oxides for Catalytic Reactive Oxygen Species Generation

用于催化活性氧生成的金属氧化物的缺陷化学

• 批准号: 1362916
• 负责人: Chin Li Cheung
• 金额: $ 40.63万
• 依托单位: University of Nebraska-Lincoln
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2018-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1362916&HistoricalAwards=false
• 关键词: Defect; Chemistry; Metal; Oxides; Catalytic

With this award, the Chemical Catalysis Program is funding Chin Li Cheung of the University of Nebraska at Lincoln and Wai-Ning Mei of the University of Nebraska at Omaha for research to investigate how certain industrially important catalysts function. The specific focus of this project seeks to understand how defects in tiny metal oxide particles lead to their ability to function as catalysts. One of oxides being studied, a substance known as cerium oxide, is used extensively as a catalyst in automobile catalytic converters, as a key component in petroleum refining, and in a wide variety of chemical manufacturing applications. Despite its widespread use and importance to industry, the mechanism for cerium oxide's catalytic activity is still not well understood. To investigate this in more detail, the group is preparing small particles of cerium oxide with imperfections, or defects, on their surfaces. These small particles are also being prepared in such a way that they contain foreign metals, or dopants, also thought to be related to their catalytic activity. The ability of these carefully prepared particles to catalyze chemical reactions is determined and, then, correlated with the defects and dopants that are present. The group is using computer modeling to more fully understand the reactions that may be taking place during catalysis. With this combined experimental and theoretical approach, the investigators are able to more completely control the catalytic activity of these small particles and more fully understand how they function. The work is having a broad impact on industry and technology, and may lead to improved catalysts for a wide variety of technological applications. The work is having a further broad impact through the engagement of students at both the undergraduate and high school level. Even younger students are being included in the work through an innovative summer camp program for middle school and home-schooled students. This project aims to develop a fundamental understanding of the role of surface-subsurface defect interactions on the chemical activity of surface binding sites that are involved in molecular adsorption in metal oxide systems of reduced dimension. Such knowledge is expected to yield catalytic pathways for reactive oxygen species (ROS) generation and annihilation with reducible metal oxide in the environment and in industrial processes. Ceria nanoparticles with different shapes, facets and chemical impurity content are being synthesized by hydrothermal methods. The kinetics of the catalytic reactions of these particles with hydrogen peroxide to generate ROS are being determined. Analysis of the kinetic data coupled with DFT modeling are used to identify the effect of subsurface defects on the molecular adsorption energies at the surface binding sites and to determine potential molecular reaction pathways.

有了这个奖项，化学催化计划将资助内布拉斯加大学林肯分校的Chin Li Cheung和内布拉斯加大学奥马哈分校的Wai-Ning Mei进行研究，以调查某些工业上重要的催化剂如何发挥作用。该项目的具体重点是了解微小金属氧化物颗粒中的缺陷如何导致其作为催化剂的能力。正在研究的氧化物之一，一种被称为氧化铈的物质，被广泛用作汽车催化转化器的催化剂，作为石油精炼的关键成分，以及各种化学制造应用。尽管它的广泛使用和重要性的工业，氧化铈的催化活性的机制仍然没有得到很好的理解。为了更详细地研究这一点，该小组正在制备表面有缺陷或缺陷的氧化铈小颗粒。这些小颗粒也是以这样的方式制备的，它们含有外来金属或掺杂剂，也被认为与它们的催化活性有关。这些精心制备的颗粒催化化学反应的能力被确定，然后与存在的缺陷和掺杂剂相关联。该小组正在使用计算机建模来更全面地了解催化过程中可能发生的反应。 通过这种结合实验和理论的方法，研究人员能够更完全地控制这些小颗粒的催化活性，并更全面地了解它们的功能。这项工作对工业和技术产生了广泛的影响，并可能导致各种技术应用的改进催化剂。这项工作正在通过本科生和高中生的参与产生更广泛的影响。甚至更年轻的学生也通过一个针对中学和家庭教育学生的创新夏令营计划被纳入这项工作。该项目旨在从根本上了解表面-次表面缺陷相互作用对表面结合位点化学活性的作用，这些结合位点参与了金属氧化物系统中的分子吸附。这些知识预计将产生催化途径的活性氧（ROS）的产生和湮灭与可还原的金属氧化物在环境中和工业过程中。采用水热法合成了不同形状、晶面和化学杂质含量的氧化铈纳米颗粒。这些颗粒与过氧化氢产生ROS的催化反应的动力学正在被确定。动力学数据的分析加上DFT建模被用来确定表面结合位点上的分子吸附能的亚表面缺陷的影响，并确定潜在的分子反应途径。

项目成果

Effect of sodium nitrate on microwave-assisted synthesis of ceria nanocubes

• DOI: 10.1016/j.matlet.2016.04.186
• 发表时间: 2016-09
• 期刊: Materials Letters
• 影响因子: 3
• 作者: Tamra J. Fisher;Meiyu Wang;Y. Ibrahim;Benjamin Steffensmeier;C. L. Cheung