The influence of surface oxygen and hydroxyl groups on the dehydrogenation of ethylene on PdAu surface alloys. A theoretical cluster model study

The ethylene dehydrogenation, which is one the key step in the VAM synthesis, is unlikely to occur on clean PdAu surface alloys due to high activation barriers. By means of density functional theory we analyzed the role of surface oxygen and hydroxyl groups in this surface reaction. The presence of the O-derived surface species sensibly lowers the energy barriers, corroborating the hypothesis that a vinyl surface species can be formed during VAM synthesis and could couples with acetate following a Langmuir-Hinshelwood-type reaction mechanism.