Multi-scale modeling of catalytic interfaces based on 2-D sub-nano surface-deposited clusters
EMSL Project ID
43995
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 (i-SNSDC), 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, and apparently erratic at small catalytic unit size. The small size regime is also where electronic structure is most tunable, with the potential to lead to most remarkable catalytic properties. However, very little electronic structure rationale exists in the traditionally rather empirical field of heterogeneous catalysis. Both experimentally, and theoretically, scientists often try a big pool of potential catalysts, with the aim of encountering a good one by chance. It is proposed to study existing catalytic systems, such as clusters of Ag, Pd, and Au on such surfaces as titania, magnesia, and ceria, and reveal the electronic reasons for stability and properties, as a function of cluster size. Subsequently, the acquired knowledge can be used to rationally design new catalytic systems. A number of methodological challenges have to be overcome to achieve the main goal. One of them is finding the global minima on the exquisitely complex potential energy surfaces (PESs) of i-SNSDC. Those global minima often take unexpected structures. The other one is comprehensively modeling i-SNSDC in the presence of the solvent in realistic conditions and yet with access to electronic structure. Currently, no tools are available for such modeling, whereas it is established that solvent (e.g. water) has a major influence on the mechanisms and energy profiles of reactions when the dipole moment of the system changes as the reaction progresses. Here, I propose to resolve these methodological issues, and then use the new methodology to study i-SNSDC, starting from explaining existing experiments, and then advancing to the design of new catalytic i-SNSDC.
Project Details
Project type
Exploratory Research
Start Date
2011-05-18
End Date
2012-05-20
Status
Closed
Released Data Link
Team
Principal Investigator
Related Publications
Alexandrova AN, MJ Nayhouse, MT Huynh, JL Kuo, AV Melkonian, G Chavez, NM Hernando, MD Kowal, and CP Liu. 2012. "Selected AB?²-/- (A = C, Si, Ge; B = Al, Ga, In) Ions: a Battle Between Covalency and Aromaticity, and Prediction of Square Planar Si in SiIn?²-/-." Physical Chemistry Chemical Physics. PCCP 14:14815–14821. doi:10.1039/c2cp41821e
Zhang J, and AN Alexandrova. 2011. "Structure, Stability, and Mobility of Small Pd Clusters on the Stoichiometric and Defective TiO2 (110) Surfaces." Journal of Chemical Physics 135:174702. doi:10.1063/1.3657833
Zhang J, and AN Alexandrova. 2012. "Double ?-Aromaticity in a Surface-Deposited Cluster: Pd4 on TiO2 (110)." The Journal of Physical Chemistry Letters 3(6):751-754. doi:10.1021/jz300158s
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
Zhang J, AP Sergeeva, M Sparta, and AN Alexandrova. 2012. "B13+: Photodriven Molecular Wankel Engine." Angewandte Chemie International Edition 51(34):8512–8515,. doi:10.1002/anie.201202674