Collaborative Research: Experimental and theoretical study on the structure and catalytic activity of metal cluster/metal oxide interfaces

合作研究：金属簇合物/金属氧化物界面的结构和催化活性的实验和理论研究

• 批准号: 1033000
• 负责人: Matthias Batzill
• 金额: $ 29.63万
• 依托单位: University of South Florida
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1033000&HistoricalAwards=false
• 关键词: Collaborative; Research; Experimental; theoretical; study

1033000BatzillThe most successful metal/metal oxide catalysts currently available involve highly-dispersed, low-concentration metal atoms embedded in a metal oxide surface. Palladium metal supported on cerium oxide, is an important example of a highly active catalyst, with applications as an automotive three-way catalyst, in catalytic combustion, and as a solid oxide fuel cell anode material. The activity of these metal/metal oxide catalysts can be uniquely controlled by the support surface structure. Furthermore, these low-concentration metal catalysts have demonstrated significant resistance against sintering, a common multi-component catalyst degradation mechanism, thus indicating superior resistance to heating/cooling cycles and changes in redox enviroment. However, the structure of the active site is challenging to define at the atomistic scale. For the metal-ceria (M/CeO2) catalytic system, dynamic restructuring occurs under reaction conditions and both the ceria and metal structure alter reactivity. So how then to explain the catalytic and performance behaviors of Pd on ceria? Three Investigators, A.C. van Duin and M. J. Janik of Pennsylvania State University and M. M. Batzill of the University of South Florida, hypothesize that mixed surface oxides of Ce1-xPdxO2-d may provide unique active sites with high activity and stability under certain reaction conditions. To confirm this and in order to fully develop the potential of Pd/CeOx and similar metal/metal oxide catalysts, they believe a detailed, atomistic-scale knowledge of the catalytic conversion mechanisms and the surface dynamics related to substrate-surface interactions is required for the Pd/ceria system. In a collaborative study, the PIs propose to utilize atomistic simulation with Reactive Force-Field (ReaxFF) and Density Functional Theory (DFT) approaches together with experimental surface science studies to investigate the dynamic structure and reactivity of Pd/CeO2 systems. The combined surface science and ReaxFF/DFT approach will provide detailed determination of the structure, stability, and activity of Ce1-xPdxO2-?Ô?nmixed oxide surfaces. This will help answer questions about this catalyst system.From the broader perspective, the combination of experimental and computational approaches applied to this complex catalytic system will advance the fundamental understanding of the effect of reducible oxide supports on catalyst stability and activity, as well as provide guidance towards the preparation of highly active M/CeO2 catalysts. Further, the development of an integrated, two-component simulation environment, which is validated against experiment is the outcome of this project. This collaboration between simulation and experiment will provide a roadmap for future catalytic research; the computational tools developed here are generally applicable, thus providing straightforward extension to other catalytic materials.The research program also closely integrates education and outreach activities. Specifically, at PSU, courses for engineers on atomistic-scale simulation methods will be introduced, which will be complemented by lectures and tutorials on experimental techniques.

1033000Batsill 目前最成功的金属/金属氧化物催化剂涉及嵌入金属氧化物表面的高度分散、低浓度的金属原子负载在氧化铈上的钯金属，是高活性催化剂的重要示例，可作为汽车三轮车应用。催化燃烧中的单向催化剂以及作为固体氧化物燃料电池阳极材料这些金属/金属氧化物催化剂的活性可以通过载体独特地控制。此外，这些低浓度金属催化剂表现出显着的抗烧结能力，这是一种常见的多组分催化剂降解机制，因此表明其对加热/冷却循环和氧化还原环境的变化具有优异的抵抗力。对于金属-二氧化铈 (M/CeO2) 催化体系来说，在反应条件下会发生动态重组，并且二氧化铈和金属结构都会改变反应性，因此很难在原子尺度上进行定义。宾夕法尼亚州立大学的 A.C. van Duin 和 M. J. Janik 以及南佛罗里达大学的 M. M. Batzill 三位研究人员发现，Ce1-xPdxO2-d 的混合表面氧化物可能提供具有高活性的独特活性位点。为了证实这一点并充分发挥 Pd/CeOx 和类似金属/金属氧化物催化剂的潜力，他们认为Pd/二氧化铈系统需要详细的、原子尺度的催化转化机制和与基底-表面相互作用相关的表面动力学知识。在一项合作研究中，PI 建议利用反应力场 (ReaxFF) 的原子模拟。和密度泛函理论 (DFT) 方法与实验表面科学研究一起研究 Pd/CeO2 系统的动态结构和反应性。表面科学和 ReaxFF/DFT 相结合的方法将提供详细的测定。 Ce1-xPdxO2-n混合氧化物表面的结构、稳定性和活性这将有助于回答有关该催化剂系统的问题。从更广泛的角度来看，应用于该复杂催化系统的实验和计算方法的结合将促进该系统的发展。基本了解可还原氧化物载体对催化剂稳定性和活性的影响，并为制备高活性 M/CeO2 催化剂提供指导。此外，还开发了集成的双组分模拟环境。经实验验证是该项目的成果。模拟和实验之间的合作将为未来的催化研究提供路线图；这里开发的计算工具具有普遍适用性，从而为其他催化材料提供了直接的扩展。该研究项目还紧密结合在一起。具体来说，在PSU，将为工程师推出原子级模拟方法课程，并辅之以实验技术讲座和教程。