Münster 1999 – wissenschaftliches Programm

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O: Oberflächenphysik

O 32: Adsorption an Oberfl
ächen (VI)

O 32.8: Vortrag

Donnerstag, 25. März 1999, 18:00–18:15, S10

Adsorption and reaction of acetic acid on Au-Pd bimetallic surfaces — •N. Takehiro, M. Sonder, and R. J. Behm — Abt. Oberfl"achenchemie und Katalyse, Universit"at Ulm, D-89069 Ulm

Adsorption and reaction of acetic acid is an important process in catalysis. We here report first results of a study on the adsorption and decompostion of acetic acid on Au-Pd(111) bimetallic surfaces using STM, HREELS and TDS, which aims at an atomic scale understanding of the reaction process on the bimetallic surface. This follows our previous research of ethylene on the same surfaces.

By controlling the amount of evaporated Au on a Pd(111) surface and annealing temperatures for alloy formation, as previously done in our group, we prepared tailored bimetallic surfaces and characterized their local chemical composition using STM. On these same Au-Pd(111) surfaces with known densities and distributions of specific sites, such as single Pd atoms, paired Pd atoms and Pd trimers surrounded by Au atoms, adsorption and decomposition of acetic acid was studied. Using HREELS, we identified adsorbates on each of the specific sites. The reaction path of these adsorbates on specific sites was studied quantitatively using TDS. Formation and decomposition of surface acetate species revealed clear site specific behaviors.