CAREER: Catalysis on Singly Dispersed Bimetallic Catalytic Sites

圣母院大学的Franklin (Feng) Tao通过CAREER奖获得了化学催化项目的资助，用于研究开发新型催化剂。这些催化剂在去除废气中的一氧化二氮等有毒气体方面表现出很好的能力。通过这项研究开发的新型催化剂由金属原子结合到氧化物载体上组成。这项工作的一个独特之处在于金属簇的小尺寸。由一个铑原子与两个氧化钴分子结合而成的体系获得了良好的结果。这些系统比工业生产中通常使用的系统小得多，这种尺寸优势可以改善性能。研究人员正在将早期对铑原子的研究扩展到其他贵金属，特别是钯和铂，希望进一步提高催化活性。该项目的更广泛影响包括开发新的高效催化剂，可用于产生新的化学燃料或从环境中去除气态污染物。该项目对下一代科学家的教育和培训产生了进一步的影响，包括参与研究小组外展工作的仍在高中的非常年轻的科学家。正在开发的催化剂是多相的，这意味着催化事件发生在由金属原子、载体或两者组成的催化位点上。本研究对双金属催化剂颗粒进行了研究。这些是双原子簇（换句话说，二聚体），通常由尺寸在纳米范围内的连续双金属位点组成。在本文研究的单分散双金属位体系中，催化位是分离的而不是连续的，因此表现出不同的电子态和分子吸附。已发现在分离的双金属位点上的反应物分子或中间体的特定结合构型可以增强对特定产物的催化选择性。目前项目重点开发3d-4d和3d-5d金属单分散双金属位催化剂。RhCo2簇已经得到了很好的结果。目前正在对Pd和Pt以及Rh与钴和氧化锌载体结合进行进一步的研究。

Franklin (Feng) Tao of the University of Notre Dame is funded through this CAREER award by the Chemical Catalysis program for research to develop new types of catalysts. These catalysts show promising abilities to remove poisonous gases such as nitrous oxide from exhaust. The new catalysts being developed through this research consist of metal atoms bonded to an oxide support. A unique feature of this work is the small size of the metal clusters. Good results have been obtained from a system consisting of a single rhodium atom bonded to two cobalt oxide molecules. These systems are much smaller than those typically used in industrial work and this size advantage could lead to improved properties. The investigators are extending earlier research with rhodium atoms to include other precious metals, in particular palladium and platinum, with the hopes to further improve catalytic activity. The broader impacts of this project include the development of new efficient catalysts that could be used to generate new chemical fuels or to remove gaseous contaminants from the environment. The project is having a further impact on the education and training of the next generation of scientists, including very young scientists still in high school who are participating in outreach efforts of the research team. The catalysts being developed are heterogeneous, which means that the catalytic event occurs on a catalytic site consisting of atoms of metal, support, or both. In this research, bimetallic catalyst particles are being investigated. These are two-atom clusters (dimers, in other words), which typically consist of continuous bimetallic sites that have a size in the nanometer range. In the systems studied here, which are singly dispersed bimetallic sites, the catalytic sites are isolated rather than continuous and thus exhibit a different electronic state and molecular adsorption. The specific binding configuration of a reactant molecule or intermediate on an isolated bimetallic site has been found to enhance catalytic selectivity for specific products. The current project focuses on the development of catalysts of singly dispersed bimetallic sites of 3d-4d and 3d-5d metals. Good results have already been found with RhCo2 clusters. Additional studies are being carried out with Pd and Pt, in addition to Rh, combined with both cobalt and zinc oxide supports.