Mechanism of the oxidation of acetylene on a Ag surface: dipped adcluster model study

The mechanism of the oxidation of acetylene on a silver surface was studied by the dipped adcluster model (DAM) combined With ab initio Hartree-Fock a nd MP2 calculations. The reactions of the hydrogen and carbon of acetylene with both molecularly and atomically adsorbed oxygens were investigated. Ou r results show that the reaction path for acetylene via epoxidation is ener getically unfavorable. On the other hand, the reaction path via hydrogen ab straction is much easier and leads to surface acetylide and hydroxyl interm ediates, and is likely the initial reaction path responsible for the comple te oxidation reaction of acetylene on a sliver surface. The reaction mechan isms derived adequately explain the available experimental results. (C) 199 9 Elsevier Science B.V. All rights reserved.