Cooperation between Dual Metal Atoms and Nanoclusters Enhances Activity and Stability for Oxygen Reduction and Evolution.

We have achieved the synthesis of dual-metal single atoms and atomic clusters that co-anchor on a highly graphitic carbon support. The catalyst comprises Ni (and Fe) nanoclusters located adjacent to the corresponding NiN (and FeN) single-atom sites, which is verified by systematic X-ray absorption characterization and density functional theory calculations. A distinct cooperation between Fe (Ni) nanoclusters and the corresponding FeN (NiN) atomic sites optimizes the adsorption energy of reaction intermediates and reduces the energy barrier of the potential-determining steps. This catalyst exhibits enhanced oxygen reduction and evolution activity and long-cycle stability compared to counterparts without nanoclusters and commercial Pt/C. The fabricated Zn-air batteries deliver a high power density and long-term cyclability, demonstrating their prospects in energy storage device applications.