Metal-embedded graphene: A possible catalyst with high activity

The catalytic activity of Au-embedded graphene is investigated by the first-principle method using the CO oxidation as a benchmark probe. The first step of CO oxidation catalyzed by the Au-embedded graphene is most likely to proceed with the Langmuir-Hinshelwood reaction (CO + O₂ → OOCO → CO₂ +O), and the energy barrier is as low as 0.31 eV. The second step of the oxidation would be the Eley-Rideal reaction (CO + O → CO₂) with a much smaller energy barrier (0.18 eV). The partially filled d states of Au are localized around the Fermi level due to the interactions between Au and the neighboring carbon atoms. The high activity of Au-embedded graphene may be attributed to the electronic resonance among electronic states of CO, O₂, and the Au atom, particularly, among the d states of the Au atom and the antibonding 2π^* states of CO and O₂. This opens a new avenue to fabricate low cost and high activity carbon-based catalyst.