Engineering the Coordination Environment of Metal Centers for Selective and High-Current CO2 Electromethanation.

Renewable energy-driven CO₂ to CH₄ conversion represents a pivotal strategy for achieving carbon neutrality, with the primary scientific challenge residing in controllably accelerating protonation kinetics. Atomically precise engineering of metal coordination catalysts offers a promising route to tailor reaction pathways. Herein, we construct a dual-active-site catalyst featuring Cu-S and Eu-N coordination centers. Through atomic-level engineering of active site microenvironments, the optimized catalyst demonstrates performance comparable to state-of-the-art systems, achieving a remarkable CH₄ Faradaic efficiency of 75.8% alongside CH₄ partial current density of 303.3 mA cm^-2. Mechanistic studies reveal that isolated Cu sites hinder C-C coupling, while the strategically dispersed Eu sites facilitate efficient water activation, which is a critical process that generates abundant protons to accelerate the rate-limiting *CO hydrogenation step. This study establishes fundamental design principles for steering selective reaction pathways through atomic-scale modulation of active site architectures and their catalytic microenvironments.