A "Pre-Constrained Metal Twins" Strategy to Prepare Efficient Dual-Metal-Atom Catalysts for Cooperative Oxygen Electrocatalysis.

Dual-metal-atom-center catalysts (DACs) are a novel frontier in oxygen electrocatalysis, boasting functional and electronic synergies between contiguous metal centers and higher catalytic activities than single-atom-center catalysts. However, the definition and catalytic mechanism of DACs configurations remain unclear. Here, a "pre-constrained metal twins" strategy is proposed to prepare contiguous FeN4 and CoN4 DACs with homogeneous conformations embedded in a N-doped graphitic carbon (FeCo-DACs/NC). A programmable phthalocyanines dimer is used as a structural moiety to anchor the bimetallic sites (containing Co and Fe) in a metal-organic framework (MOF) to achieve delocalized dispersion before pyrolysis. The resultant FeCo-DACs/NC exhibits excellent electrochemical performance in oxygen electrocatalysis and rechargeable Zn-air batteries. Theoretical calculations demonstrate that the synergetic interaction of adjacent metals optimizes the d-band center position of metal centers and balances the free energy of the *O intermediate, thereby improving the oxygen electrocatalytic activity. This work opens up an avenue for the rational design of DACs with tailored electronic structures and uniform geometric configurations.