Structural, electronic and catalytic performances of single-atom Fe stabilized by divacancy-nitrogen-doped graphene

Inspired by the experimental discovery of the configuration of a one central transition metal and four surrounding N atom doped graphene sheet (M-GN4), we systemically study the geometry and electronic and catalytic properties of a single-atom Fe embedded GN4 sheet (Fe-GN4) using first-principles calculations. It is found that the neighboring N atoms in graphene strongly stabilize a single Fe atom and make the doped Fe atom more positively charged, which helps to regulate the stability of reactive gases. Besides, the adsorption of gas molecules can modulate the electronic structure and magnetic property of the Fe-GN4 system. Moreover, the catalytic reactions of CO oxidation on the Fe-GN4 substrate are comparably investigated in terms of the Langmuir-Hinshelwood (LH) and Eley-Rideal (ER) mechanism. The results show that the LH reaction as the starting state is energetically more favorable than the ER reaction, since the catalytic process has much smaller energy barriers (0.13 eV) and then promotes the CO oxidation reaction. Therefore, the stable configuration of Fe-GN4 would be a highly efficient catalyst for CO oxidation, which provides a clue for designing atomic-scale catalysts in energy-related devices.