Constructing Asymmetric Sn‐Cu‐C Interface via Defective Carbon Trapped Atomic Clusters for Efficient Neutral Nitrate Reduction

Abstract Multi‐atom cluster (MACs) catalysts have recently attracted significant research interest for their potential to catalyze multi‐electron reactions through cooperative interactions among adjacent active sites. However, the controllable synthesis of MACs and the electrocatalytic mechanism understanding of their synergistic effects remain challenging. Herein, we develop a defect engineering strategy to anchor bimetallic SnCu atomic clusters at defective graphene (SnCu‐DG) via carbon defect‐mediated atomic trapping, wherein edge defects act as confined reactors for cluster nucleation. Taking nitrate reduction as an example, the SnCu‐DG catalyst achieves a high NH 3 Faradaic efficiency (99.5%) at neutral electrolyte condition, accompanied by a record intrinsic activity of 2.61 × 10 −17 mmol h −1 site Cu −1 , surpassing Cu‐DG and SnCu‐G counterparts by 16.0‐ and 7.8‐fold, respectively. X‐ray adsorption spectra and theoretical calculations reveal the electrons transfer between Cu and carbon defect sites while Sn incorporation intensifies asymmetric charge polarization across the Sn‐Cu‐C interface. This dual modulation collaboratively optimizes the catalytic microenvironment, simultaneously enhancing *NO 2 − adsorption, accelerating water dissociation kinetics, and breaking the intrinsic linear scaling between intermediate adsorption and hydrogenation.