CO oxidation on atomic nickel/phosphorene nanosheet: An efficient single-atom catalyst

Various metals decorated phosphorene nanosheet as single-atom catalyst (SAC) for CO oxidation have been investigated systematically by employing spin-polarized density functional theory. Ni-phosphorene is found to be the promising SAC for CO oxidation after comparing with other noble and non-noble metal candidates, such as Fe, Co, Cu, Al, Ag, Au, and Pt. Moreover, the structure of Ni-phosphorene remains stable at the end of 5 ps under 300 K using first-principles molecular dynamics simulations. Additionally, O-2 and CO are difficult to dissociate on Ni-phosphorene at room temperature because their dissociation energies are greater than 1 eV in possible paths. Three feasible reaction mechanisms (Langmuir-Hinshelwool (LH), Eley-Rideal, and Termolecular Eley-Rideal) are taken into account to seek the path with the lowest energy barrier. The LH mechanism is the most favorable one with the lowest energy barrier (0.59 eV) in the rate-determining step, which is facile to occur under ambient temperature. Our results provide theoretical guidance to design highly active heterogeneous catalysts based on phosphorene substrate for CO oxidation at low temperature.