Density functional theory calculations on the CO catalytic oxidation on Al-embedded graphene

The oxidation of CO molecules on Al-embedded graphene has been investigated by using the first principles calculations. Both Eley–Rideal (ER) and Langmuir–Hinshelwood (LH) oxidation mechanisms are considered. In the ER mechanism, an O2 molecule is first adsorbed and activated on Al-embedded graphene before a CO molecule approaches, the energy barrier for the primary step (CO + O2 → OOCO) is 0.79 eV. In the LH mechanism, O2 and CO molecules are firstly co-adsorbed on Al-embedded graphene, the energy barrier for the rate limiting step (CO + O2 → OOCO) is only 0.32 eV, much lower than that of ER mechanism, which indicates that LH mechanism is more favourable for CO oxidation on Al-embedded graphene. Hirshfeld charge analysis shows that the embedded Al atom would modify the charge distributions of co-adsorbed O2 and CO molecules. The charge transfer from O2 to CO molecule through the embedded Al atom plays an important role for the CO oxidation along the LH mechanism. Our result shows that the low cost Al-embedded graphene is an efficient catalyst for CO oxidation at room temperature.