Affiliations: Labs. Química Computacional y Fisicoquímica de Superficies, Centro de Química, IVIC, Caracas, Venezuela | [x] Centro de Química, Instituto Venezolano de Investigaciones Científicas, IVIC, Caracas, Venezuela | [y] Departamento de Química, Instituto Universitario de Tecnología FRP, Caracas, Venezuela
Correspondence:
[*]
Corresponding author: Beulah Griffe, Labs. Química Computacional y Fisicoquímica de Superficies, Centro de Química, IVIC, Apdo. Postal 20632 Caracas 1020-A, Venezuela. E-mail: [email protected]; [email protected]
Abstract: Quantum chemistry calculations were done, using the ONIOM2 methodology at two different levels of calculation, B3LYP for the high level and UFF for the low level. These calculations were performed on Au5/SAPO-11, Au6/SAPO-11, CO-Au5/SAPO-11 and CO-Au6/SAPO-11 aggregates to analyze the geometries of small clusters of Au5 and Au6 on SAPO-11 support. Au5 cluster presents a pentagonal structure in Au5/SAPO-11. Au6 aggregate shows a “multi triangular” structure (as from a trapezoidal “W shaped” Au5) in Au6/SAPO-11. Au5 is also obtained as an “X shaped” structure. Similarly another Au6 aggregate configuration is obtained also multi triangular but as from X shape Au5 cluster. The CO interaction with Au5 and Au6/SAPO-11 is studied. The formation energy ΔEF of the aggregates, the CO adsorption energy ΔEads on them and CO frequency are presented.
