Ordered Copper Triangular Atomic Sites for Industrial‐Grade Electromethanation of CO₂ via Self‐Regulated Adsorption of Reactants

Copper single‐atom catalysts have shown considerable potential for electrocatalytic CO 2 reduction reaction (CO 2 RR) to methane but face constraints of low selectivity at industrial‐grade current densities (>400 mA cm −2 ) and limited economic viability. Herein, we report an ion exchange strategy to precisely construct ordered Cu triangular atomic sites loaded on poly(heptazine imide) (Cu TAS/PHI), achieving a methane Faradaic efficiency (FE) of 80.5% at 400 mA cm −2 and >60% across 100–800 mA cm −2 . Remarkably, it enables CO 2 deuteration to high‐value methane‐ d 4 with an FE of 75.1% at 700 mA cm −2 and an estimated annual return on investment of 425.35%. In situ spectroscopy and theoretical calculations demonstrate that Cu triangular atomic sites enable strengthened adsorption and activation of CO 2 , as well as balanced proton supply via self‐regulated adsorption of reactants, thus favoring CO 2 deep hydrogenation over hydrogen evolution. Moreover, Cu TAS/PHI unlocks an energetically favorable *C(OH) 2 pathway, circumventing the conventional *CO pathway that typically yields diverse CO 2 RR products. This work demonstrates a strategy to construct ordered multiatomic sites for highly selective CO 2 RR at industrial‐grade current density and highlights the extraordinary financial potential of electrocatalytic CO 2 RR to produce high‐value deuterated chemicals.