Near‐Unity Selectivity Inversion Between CO ₂ Electroreduction and H ₂ Evolution via Atomic Coordination Editing

ABSTRACT Precise atomic coordination editing of single‐atom catalysts (SACs) provides an effective strategy to tune their electronic structures and catalytic selectivity. Yet, achieving near‐unity selectivity inversion between two competing reactions, allowing deliberate control over the preferred pathway, remains a significant challenge. Here, we demonstrate that single‐atom coordination editing of NiN ₄ ‐based SACs enables precise control over reaction selectivity, allowing a near‐complete switch between CO ₂ reduction (CO ₂ RR) and H ₂ evolution (HER). While the symmetrically coordinated NiN ₄ motif preferentially stabilizes ^* H over ^* COOH, resulting in exclusive HER, replacing a nitrogen coordination atom in the NiN ₄ site with carbon (NiN ₃ C) breaks the structural symmetry, upshifts the d ‐band center, and polarizes the charge distribution, thus lowering the ^* COOH activation barrier and favoring CO ₂ ‐to‐CO conversion. Guided by these theoretical insights, the corresponding catalysts were synthesized and verified by multiple characterization techniques. Unlike NiN _4, which exhibits exclusively HER‐dominated behavior, NiN ₃ C achieves ∼99% CO Faradaic efficiency across a wide pH range, a partial current density of ∼840 mA cm ⁻² , and a carbon energy efficiency of 77%. Notably, a turnover frequency of 6.03 × 10 ⁵ h ⁻¹ and > 100 h stability at industrial‐level currents surpass previously reported benchmarks. In situ ATR‐SEIRAS and charge‐density analysis revealed that the NiN ₃ C structure weakens Ni‐centered σ interactions while enhancing C‐center π coupling with ^* COOH, thereby shifting ^* COOH adsorption from the Ni center to an adjacent C site, enabling CO ₂ RR selectivity. This study establishes an atomic coordination‐editing strategy that provides mechanistic insight into catalytic pathway switching and enables high‐performance electrocatalysis toward desired products.