In situ reconstructed interface-engineered Cu nanosheets for industrial-current-density CO2 electroreduction to C2+ products
Electroreduction-derived Cu-based two-dimensional materials are promising catalysts for CO2 conversion to C2+ products, yet the role of reconstructed interface structures remains ambiguous. We fabricate interface-engineered Cu nanosheets via in situ pre-electrolysis of kilogram-scale brochantite nanosheet precursors. Lead underpotential deposition and OH− electrosorption analysis confirm abundant Cu(100)/Cu(110) interfaces. In situ attenuated total reflection-surface enhanced infrared absorption spectroscopy reveals C–C coupling pathways involving hydrogenation of *CO to *CHO, followed by coupling to *COCHO. Operando Raman spectra demonstrate that these interfaces provide sufficient *CO surface coverage, facilitating deep coupling reactions. Density-functional-theory calculations indicate that Cu(100)/Cu(110) interfaces reduce the energy barrier of the rate-determining hydrogenation step by 0.16 eV and promote *CO and *CHO coupling. Consequently, the Cu nanosheets achieve a C2+ Faradaic efficiency of 80.4% at an industrial current density of 800 mA cm−2, surpassing most reported Cu-based catalysts. This work establishes a molecular-level understanding of interface engineering for CO2 electroreduction, leveraging scalable precursor synthesis and precise characterization.