Electron-Coupling Effect Modulating the d-Band Center of Asymmetric Cobalt Single-Atom Sites for Electrocatalytic Oxygen Reduction

We introduce an aggregation-induced deposition approach for rapidly synthesizing asymmetric Co-N₃O single-atom sites (SAs) with a precise atomic configuration on a hollow carbon matrix (Co-SAs/NHC). This design leverages the electron-coupling effect between Co SAs across adjacent carbon layers, enhancing the intrinsic activity and durability of the catalyst. In the ORR, the Co-SAs/NHC catalyst displayed a half-wave potential improvement of 51 mV, achieving a mass activity 5-fold that of commercial Pt/C. Remarkably, after 30 000 potential cycles, there was a negligible half-wave potential loss of just 17 mV. Density functional theory calculations revealed that the adjacent Co-N₃O sites optimized the electronic structure and d-band center of the Co atom, thereby reducing the adsorption energy of the OH* intermediates. This work offers a pathway for developing industrial-grade single-atom catalysts (SACs) with satisfactory catalytic activity and durability.