Atomically Precise Dinuclear Site Active toward Electrocatalytic CO₂ Reduction

The development of atomically precise dinuclear heterogeneous catalysts is promising to achieve efficient catalytic performance and is also helpful to the atomic-level understanding on the synergy mechanism under reaction conditions. Here, we report a Ni₂(dppm)₂Cl₃ dinuclear-cluster-derived strategy to a uniform atomically precise Ni₂ site, consisting of two Ni₁-N₄ moieties shared with two nitrogen atoms, anchored on a N-doped carbon. By using operando synchrotron X-ray absorption spectroscopy, we identify the dynamically catalytic dinuclear Ni₂ structure under electrochemical CO₂ reduction reaction, revealing an oxygen-bridge adsorption on the Ni₂-N₆ site to form an O-Ni₂-N₆ structure with enhanced Ni-Ni interaction. Theoretical simulations demonstrate that the key O-Ni₂-N₆ structure can significantly lower the energy barrier for CO₂ activation. As a result, the dinuclear Ni₂ catalyst exhibits >94% Faradaic efficiency for efficient carbon monoxide production. This work provides bottom-up target synthesis approaches and evidences the identity of dinuclear sites active toward catalytic reactions.