Coadsorption of hydrogen and carbon monoxide on Ni(100) and Pd(100) - hydrogen recombination, dissolution and desorption

Abstract

The adsorption of carbon monoxide on hydrogen covered Ni(100) and Pd(100) surfaces has been investigated using electron energy loss Spectroscopy (HREELS), low energy electron diffraction (LEED) and thermal desorption Spectroscopy (TDS). On the Ni surface, part of the adsorbed H recombine to form chemisorbed H 2 and part of the CO molecules change adsorption sites. The H 2 molecules seem to be stabilized by the specific CO environment. The Pd surface shows a more complex behaviour. The hydrogen is partly displaced subsurface. For a CO coverage around 0.5 monolayers an intermediate state preceding H-dissolution can be isolated.