Charge exchange in CO-oxidation with supported gold clusters
Department of Chemistry, University of Chicago - 929 East 57th St., Chicago, IL 60637, USA
2 Joint Institute for High Temperatures of RAS - 13, bldg. 2 Izhorskaya str., Moscow, 125412, Russia
Accepted: 16 February 2012
The oxidation of CO molecules bound to supported gold clusters evolves through a series of configurational changes along the potential energy surface of the total system. The possibilities of theoretical approaches and models for description of catalytic processes are analyzed, and, in particular, the vulnerability of the DFT method is shown for such processes. The analysis of experimental data shows that the formation of the CO2 molecule occurs via a straightforward chemical process, which competes with a charge exchange process involving formation of negatively charged gold clusters. The structure of the gold cluster for one pathway involves the planar form whereas the other pathway goes via the two-layer cluster structure. From this information, we can infer the selectivity and efficiency of the catalyst as functions of the cluster size and determine that the typical distance for the tunnelling electron transition to form negatively charged clusters is 1–2 nm that means that this electron is taken from the support.
PACS: 36.40.-c – Atomic and molecular clusters / 64.70.-p – Specific phase transitions / 82.20.Kh – Potential energy surfaces for chemical reactions
© EPLA, 2012