Surface-mounted bi-metallic sub-nano clusters as catalysts for endothermic cooling
EMSL Project ID
48054
Abstract
The ultimate objective of the proposed research is understanding and design of novel catalytic surfaces based on sub-nano surface-deposited clusters, with a particular application to hydrogenation/de-hydrogenation of various hydrocarbons and water activation to promote carbon gasification to catalyze endothermic cooling of surfaces in extreme environments. Surface deposited nano-clusters are very promising new catalysts, because of the unique electronic structure effects in them, such as presence of corner and edge sites, dangling orbitals, separation of bands into MOs, and small HOMO-LUMO gaps. At the fundamental level, all material 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 and quantitative understanding of chemical bonding on the material surface, along with their resultant structure and properties. This understanding is the key feature of the proposed theoretical research.
It is proposed to study, using electronic structure calculations, existing and new catalytic systems: bi-metallic clusters of Pt, doped with other metals (e. g. Zn or Au), as well as other transition metals, on various oxide surfaces—both stoichiometric and defective. For systems where catalytic behavior has been 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 this, we will advance our research toward new catalytic systems, such as Zn-doped clusters of Pt. These systems are expected to be even better catalysts for endothermic cooling in extreme environments, 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 perspective, which will be vital in future interpretations 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
2013-12-02
End Date
2014-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Related Publications
Dadras MJ, L Shen, and AN Alexandrova. 2015. "Pt–Zn Clusters on Stoichiometric MgO(100) and TiO2(110): Dramatically Different Sintering Behavior." Journal of Physical Chemistry C 119(11):6047–6055. doi:10.1021/jp512277x
Ha MA, MJ Dadras, and AN Alexandrova. 2014. "Rutile-Deposited Pt–Pd clusters: A Hypothesis Regarding the Stability at 50/50 Ratio." ACS Catalysis 4(10):3570–3580. doi:10.1021/cs5011426
Shen L, MJ Dadras, and AN Alexandrova. 2014. "Pure and Zn-doped Pt Clusters go Flat and Upright on MgO(100) ." Physical Chemistry Chemical Physics. PCCP 16(48):26436--26442. doi:10.1039/c4cp01877j