Chemisorption and thermal decomposition of acetylene and ethylene on Pd(110): HREELS, TDS and LEED studies

The adsorption and thermal evolution of acetylene and ethylene on Pd(110) have been studied using high-resolution electron energy loss Spectroscopy, multiplexed thermal desorption spectroscopy and low-energy electron diffraction. For a small exposure at 90 K, acetylene is chemisorbed molecularly in a single state, and is located in the μ 2 -site with its CC bond axis inclined to the surface plane; one of the CH groups is hydrogen-bonded to the surface. For a large exposure, acetylene is adsorbed in several states. Ethylene is π-bonded to the Pd(110) surface at 90 K. The dehydrogenation processes of acetylene and ethylene on Pd(110) by the heat treatment are discussed.