Adsorption and reaction of ethylene and hydrogen on Rh(100) surface

Adsorption and reaction of ethylene on clean and H-presaturated Rh(100) have been investigated using HREELS. Adsorption of ethylene on H-presaturated Rh(100) surface at 110 K leads to a π-bonded state, as indicated by a πσ parameter of 0.39 equivalent to that of Zeiseʹs salt. The formation of an ethyl intermediate from the π-bonded ethylene by insertion of preadsorbed H atom already takes place even at 110 K, leading to the evolution of ethane below 200 K. Upon heating, CC bond breakage is promoted on the H-preadsorbed surface, where the strength of metal to H in the adsorbed ethylene is considered to be reduced by preadsorbed hydrogen.