C–H bond activation of methane on clean and oxygen pre-covered metals: A systematic theoretical study

Density functional theory calculations are presented for adsorption and dissociation of CH4 on clean and oxygen atom pre-adsorbed metal surfaces (Cu, Ag, Au, Ni, Pd, Pt, Ru, Rh, Os, Ir, and Mo). The total energy change and the activation barrier have been calculated for the direct and the oxygen-assisted cleavage of the C–H bonds. Our results indicate that pre-adsorbed oxygen promotes the CH4 dissociation process on IB group metal surfaces, but inhibits the dissociation process on transition metal surfaces. A good Brønsted–Evans–Polanyi correlation for CH4 dissociation on clean and atomic oxygen pre-adsorbed metal surfaces is found, which is helpful to reveal the nature of CH4 dissociation. From the analysis of activation barrier, we expect our work can provide a clear understanding of the nature of CH4 dissociation.