Ternary Synergism of Heterogeneous M¹N₄‐C‐M²N₄‐C‐M³N₄ Single‐Atom Sites to Manipulate the Electrocatalytic Pathway for Zn‐Air Battery and Water Splitting

Abstract Ternary metal catalysts hold great promise in complementary functionality and synergistic interplay, which are promising for combined reactions involving multi‐intermediates. However, simultaneously downscaling all three metal species into single‐atom level still remains challenge. Herein, a universal metal encapsulation‐segregation‐overlay strategy is designed to realize the fabrication of heterogeneous M¹N₄‐C‐M²N₄‐C‐M³N₄ ternary single‐atoms (TSAs)‐based catalysts, with well‐defined configuration and threefold enhancement of single‐atom loading (IrPtCu TSAs, up to 21.24 wt%). Taking non‐precious‐metallic CoN₄‐C‐NiN₄‐C‐FeN₄ TSAs for instance, the integration of triple‐decker single‐atoms affords strong electronic reciprocity, with interbedded Ni donating electrons for both Fe and Co, thereby simultaneously enhancing the catalytic activity for oxygen reduction, oxygen evolution, and hydrogen evolution through a “site‐selective master‐servant” mechanism. Thanks to the mutually assisted tri‐functionality, the CoN₄‐C‐NiN₄‐C‐FeN₄ TSAs‐electrode takes on alternatating master/servant roles to enable outstanding recyclability for energy devices. This work breaks the obstructions in synthesis and fundamental study of TSAs, providing insights into atomic material design for complicated catalytic reactions.