CH3OH + 2H (2Sg) hydrogen abstraction reactions occurring in the presence of a copper tetramer: A DFT study

The density functional approximation M05 with 6‐31G** and m‐6‐31G* basis sets were used to calculate the classical barrier heights, structures, reaction energies, and enthalpies of the hydrogen ion reaction paths of 2H + (CH3OH)·Cu4 → 2H2 + (COH2)·Cu4, which is a prototype system for dehydrogenation of methanol catalyzed by copper clusters, consisting of two sequential elementary reactions of the methanol combustion mechanism. Electronic structure and intermolecular/intramolecular bond energies were computed as well as the energy variations for the reaction both free and in the presence of the tetramer copper cluster. It was observed that the first dehydrogenation path, related to the ion from hydroxyl group of methanol, shows no classical barrier in this level of calculation. We have demonstrated that the planar rhombus cluster Cu4 has bonding properties which mimic quantitatively catalytic properties for some elementary reactions in the methanol combustion mechanism. © 2012 Wiley Periodicals, Inc. Electronic structure calculations within the cluster approach for a catalyst active site can provide complementary information for the fundamental processes involved in the research and development of catalysts. Hydrogen ions are important reactions in the methanol combustion mechanism, and this work's main goal consists in characterizing the reaction pathways of methanol hydrogen ion assisted by a copper tetramer.