Ordered Copper Triangular Atomic Sites for Industrial-Grade Electromethanation of CO

Copper single-atom catalysts have shown considerable potential for electrocatalytic CO2 reduction reaction (CO2RR) 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 CO2 deuteration to high-value methane-d4 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 CO2, as well as balanced proton supply via self-regulated adsorption of reactants, thus favoring CO2 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 CO2RR products. This work demonstrates a strategy to construct ordered multiatomic sites for highly selective CO2RR at industrial-grade current density and highlights the extraordinary financial potential of electrocatalytic CO2RR to produce high-value deuterated chemicals.