C–H Bond Activation of Methane via σ–d Interaction on the IrO₂(110) Surface: Density Functional Theory Study

Abstract

The adsorption and dissociation of methane on the IrO2(110) surface were investigated by density functional theory calculations. The adsorption energy of methane obtained in this study is −0.41 eV on the stoichiometric surface and −0.63 eV on the oxygen-rich surface, which are significantly higher than those calculated recently on other different catalytic systems. Analyses from density of states and electron density difference show a special interaction between the C–H bonding orbital and the dz2 orbital of surface iridium atom. In addition, the first hydrogen atom abstraction of methane by the IrO2(110) surface is a reaction with low barrier and high exothermic energy. The lower reaction barrier than the desorption energy indicates that the IrO2(110) surface could provide not only high sticking coefficient but also high turnover frequency in methane dissociation reaction.