Identifying available adsorption sites on Au-Pd alloys by FTIR spectroscopy and Monte Carlo simulations

MANZI, SERGIO; BOSCO, MARTA V.; BRITES HELÚ, MARIELA A.; BALDO, ALINA; COLLINS, SEBASTIAN E.; CALAZA, FLORENCIA C.

Pittsburgh, PA

Conferencia; AVS 68th International Symposium & Exhibition; 2022

American Vacuum Society (AVS)

Available adsorption sites on the surface of bimetallic AuPd compounds were studied by comparison of experimental results of CO adsorption, used commonly as a probe site molecule, on catalysts (powders) AuPd/CZ (ceria-zirconia) prepared in a relation 1:1 (Au:Pd), and on catalyst model surfaces prepared over single crystals. On both systems the sites exposed for CO adsorption are modified by calcining or heating the material to specific temperatures, allowing surface and bulk Au and Pd reordering. The spectroscopy results from both systems present some degree of agreement supporting in this way the need for interdisciplinary research to study catalytic systems. Furthermore, the system was also characterized by Monte Carlo simulations, which give an explanation for the increased availability of Pd atop sites experimentally observed, by forming Pd chains across the surface and avoiding 3-fold site formation due to agglomeration of Pd atoms.