Inter‐Site Distance Engineering of Heteronuclear Pd─Cu Atomic Sites Enables High‐Efficiency Cross‐Coupling Reactions Through Atomic‐Scale Locking Pockets

Abstract Precision engineering of intermetallic spacing and electronic synergy in heteronuclear dual‐atom catalysts (DACs) remains a pivotal challenge. Herein, the synthesis of a nitrogen‐doped hollow carbon‐supported Pd─Cu DAC is reported via a polymer‐mediated confinement strategy, achieving sub‐3 Å Pd─Cu spacing. This atomic‐scale proximity, stabilized by 2N‐bridged heteronuclear pairs, supports a charge asymmetry configuration, which enables cooperative catalysis of reactants within active pockets, thereby enhancing the Sonogashira coupling reaction performance. Specifically, electron‐rich Pd activates C─X bonds (X═I, Br, Cl) via optimized electronic structure, while electron‐deficient Cu centers stabilize alkynyl intermediates, effectively suppressing byproducts. The Pd─Cu/NC demonstrates exceptional performance, achieving high selectivity and 94% yield at a turnover frequency of 889 h⁻¹, with ultralow Pd usage (2 ppm). This significantly outperforms long‐distance Pd/Cu single‐atom catalysts (79% yield) and inactive PdCu alloys. Operando spectroscopy and theoretical calculations confirm that fast intermediate transfer between Pd─Cu sites reduces the energy barriers for C─C coupling compared to isolated Pd site systems. The active locking architectures of intimate Pd─Cu sites ensure ligand‐free operation, excellent durability, and broad substrate scope, including bromo‐/chloroarenes, which are challenging in traditional heterogeneous catalysis. This work highlights atomic‐level distance engineering as a key strategy for enhancing site cooperativity efficiency.