The adsorption of CO, O2, and H2 on Pt(100)-(5×20)

• Published in: Surface science Vol. 102; no. 1; pp. 99 - 117
• Main Authors: Barteau, M.A., Ko, E.I., Madix, R.J.
• Format: Journal Article
• Language: English
• Published: 01.01.1981
• ISSN: 0039-6028
• DOI: 10.1016/0039-6028(81)90310-1

The adsorption/desorption characteristics of CO, O2, and H2 on the Pt(100)-(5 x 20) surface were examined using flash desorption spectroscopy. Subsequent to adsorption at 300 deg K, CO desorbed from the (5 x 20) surface in three peaks with binding energies of 28, 31.6, and 33 kcal/gmol. These states formed differently from those following adsorption on the Pt(100)-(1 x 1) surface, suggesting structural effects on adsorption. Oxygen could be readily adsorbed on the (5 x 20) surface at temperatures above 500 deg K and high O2 fluxes up to coverages of 2/3 of a monolayer with a net sticking probability to saturation of > = 10-3. Oxygen adsorption reconstructed the (5 x 20) surface, and several ordered LEED patterns were observed. Upon heating, oxygen desorbed from the surface in two peaks at 676 and 709 deg K; the lower temperature peak exhibited attractive lateral interactions evidenced by autocatalytic desorption kinetics. Hydrogen was also found to reconstruct the (5 x 20) surface to the (1 x 1) structure, provided adsorption was performed at 200 deg K. For all three species, CO, O2, and H2, the surface returned to the (5 x 20) structure only after the adsorbates were completely desorbed from the surface. 22 ref.--AA