Precisely controlling the local coordination structure of atomic Fe sites has been widely recognized as the key to attain highly efficient oxygen reduction reaction (ORR) catalysts for replacing Pt-based materials. Here, we use pre-synthesized pentagon-rich defective carbon (PDC) as a matrix material to realize a custom-made pentagon defect-coordinated Fe-C5 configuration via a chemical vapor deposition method. The intrinsic activity of as-prepared PDC-supported Fe single-atom catalysts (Fesac-PDC), in terms of specific kinetic current density (Jk-specific), mass activity, and turnover frequency (TOF), is valued to be several times higher than that of other N-coordinated counterparts. Density functional theory (DFT) calculations demonstrate that the excellent ORR activity of pentagon-type Fe-C5 sites originates from the optimized electronic state with more charge transfer and down-shifted d-band center. Our work gives new insight into boosting the ORR performance of atomic single-site catalysts via purposely and precisely constructing more unique defect-stabilized single atomic species.

Precisely constructing pentagon trapped single-atomic iron sites in defective carbon for efficient oxygen electroreduction