Surface-supported sub-nano clusters as catalysts
EMSL Project ID
47412
Abstract
The ultimate objective of the proposed research is fundamental understanding and design of novel catalytic interfaces based on ultra-small, sub-nano surface-deposited clusters, with a particular application to CO oxidation. Small deposited clusters are very promising new catalysts, because of the unique electronic structure effects in them, such as presence of corner and edge sites, strain energy, dangling orbitals, separation of bands into MOs, and yet small HOMO-LUMO gaps. The electronic structure – property dependence is prominent, apparently erratic, and highly tunable, at small catalytic unit size. At the most fundamental level, all materials properties, including catalytic activity, arise from the bonding and interactions of the constituent atoms. Thus, in order to approach catalyst design rationally and with a reasonable degree of predictability, it is critical to have a qualitative understanding of chemical bonding motifs attainable in materials, along with their resultant structure / properties. This understanding is the key feature of the proposed theoretical research.
It is proposed to study, using electronic structure calculations, both existing and new catalytic systems: clusters of Pd, pure and doped with Au, on such surfaces as stoichiometric and defected titania, and known topological insulators, such as Bi2Se3. For systems where catalytic behavior was observed experimentally, we will explain the size/composition/activity dependences, as well as cluster shapes and stability, in terms of chemical bonding within the cluster, between the cluster and the surface, and between the catalytic interface and the substrate of the catalyzed reaction. After that, we will advance our research toward new catalytic systems, such as Au-doped clusters of Pd, and also clusters deposited on topological insulators. The former are expected to yield bifunctional catalysts. The latter are completely new systems, hitherto unexplored in catalysis. They are expected to be even better catalysts than clusters deposited on semiconductors, due to the robust nature of the high energy electronic states on their surfaces. This research will be facilitated by existing electronic structure methods, as well as new theoretical methodologies.
The deliverables of the proposed research include fundamental understanding of selected catalytic systems from the chemical bonding prospective, which will be instrumental in further interpretation of experimental data, and catalyst design. Additionally, new catalytic systems will arise.
We request computer time at the EMSL Chinook machine to make this research possible.
Project Details
Project type
Exploratory Research
Start Date
2012-09-28
End Date
2013-09-29
Status
Closed
Released Data Link
Team
Principal Investigator
Related Publications
Alexandrova AN, MR Nechay, BR Lydon, DP Buchan, AJ Yeh, MH Tai, IP Kostrikin, and L Gabrielyan. 2013. "The same in the bulk but different as clusters: X3Y3 (X = B, Al, Ga; Y = P, As)." Chemical Physics Letters 588:37–42. doi:10.1016/j.cplett.2013.10.003
Zhang J, and AN Alexandrova. 2013. "The Golden Crown: A Single Au Atom that Boosts the CO Oxidation Catalyzed by a Palladium Cluster on Titania Surfaces." Journal of Physical Chemistry Letters 4(14):2250–2255. doi:10.1021/jz400981a