A General Metal Ion Recognition Strategy to Mediate Dual-Atomic-Site Catalysts.

Heterogeneous dual-atomic-site catalysts (DACs) hold great potential for diverse applications. However, to date, the synthesis of DACs primarily relies on different atoms freely colliding on the support during synthesis, principally leading to low yields. Herein, we report a general metal ion recognition (MIR) strategy for constructing a series of DACs, including but not limited to FeSn, FeCo, FeNi, FeCu, FeMn, CoNi, CoCu, Co, and Cu. This strategy is achieved by coupling target inorganometallic cations and anions as ion pairs, which are sequentially adsorbed onto a nitrogen-doped carbon substrate as the precursor. Taking the oxygen reduction reaction as an example, we demonstrated that the FeSn-DAC synthesized through this strategy delivers a record peak power density of 1.218 W cm under 2.0 bar H-O conditions and enhanced stability compared to the single-atom-site FeN. Further study revealed that the superior performance arises from the synergistic effect of FeSn dual vicinal sites, which effectively optimizes the adsorption of *OH and alleviates the troublesome Fenton-like reaction.