Metalloid Coordination Reinforcing Electronic Synergy in Dual-Atom Sites for Large-Scale CO₂ Electrolysis

Reinforcing electronic synergy in dual-atom catalysts (DACs) is critical yet challenging for boosting electrocatalytic CO₂ reduction (ECR) performances. Herein, we develop a versatile strategy introducing metalloid B to construct B,N co-coordination dual sites featuring polarized (N-B)_n bridges, enforcing electron delocalization between metal centers in DACs. Taking NiFe DACs as an example, the as-obtained NiFe/BNC achieves 99% CO Faraday efficiency (FE_CO) and 55.7% full-cell energy efficiency (200 mA cm^-2) in a membrane electrode assembly (MEA) cell, markedly outperforming the common N-coordinated counterpart (NiFe/NC) and representing state-of-the-art performance. Moreover, upon scaling the cell area to 100 cm², this catalyst maintains >95% FE_CO during high-current electrolysis at 1-6 A. Even at -53 °C, it sustains >98% FE_CO across 50-250 mA cm^-2, confirming the feasibility for in situ fuel production on Mars. Systematic investigations reveal B,N co-coordination induces reversed electron transfer (Fe→Ni), distinct from weakly interacting NiFe/NC. This facilitates *COOH formation on electron-enriched Ni sites and accelerated CO desorption from electron-deficient Fe sites, synergistically enhancing ECR. Simultaneously, B sites promote water dissociation by adsorbing *OH intermediates, further boosting overall performance. Notably, this strategy shows broad versatility across Ni-Fe, Ni-Cu, Ni-Co, and Ni-Mn systems, opening new avenues for advanced DAC design.