Collect. Czech. Chem. Commun. 1987, 52, 2392-2400

Adsorption of oxygen and carbon monoxide on DymCun bimetallic surfaces at room temperature

Josef Kopešťanský

Institute of Organic Chemistry and Biochemistry, Czechoslovak Academy of Sciences, 166 10 Prague 6


The adsorption of oxygen and carbon monoxide on surfaces of dysprosium, copper, and their bimetallic “alloys” DymCun was studied by work function measurements. In the starting stage of adsorption of oxygen, copper surfaces are more reactive than dysprosium surfaces, and bulk oxide appears in the sub-surface copper layers at room temperature; this was also observed for the bimetallic surfaces, where the starting adsorption of oxygen took place nearly exclusively on copper. With dysprosium, the bulk oxide did not form at room temperature; instead, oxygen was adsorbed on the surface to form a layer consisting of species of two kinds with substantially different dipole moments. Carbon monoxide practically did not adsorb on copper at 25 °C, whereas on dysprosium it exhibited dissociative adsorption. On the bimetallic surfaces (DyCu and DyCu6) the amount of adsorbed CO decreased proportionally to the increasing Cu content of the alloy. Segregation of copper in the surface layer, observed for the bimetallic DymCun “alloys”, resulted in an additional decrease in the amount of adsorbed CO.