Curvature-induced asymmetric C-C coupling for CO2 electroreduction to multicarbon products

Understanding how nanoscale geometric parameters govern catalytic behavior is crucial for the rational design of efficient electrocatalysts for electrocatalytic CO 2 reduction (ECO 2 R). Here, we establish a curvature-engineered platform based on phase-pure Cu nanoparticles, in which geometric curvature is effectively decoupled from composition and crystal phase. In flow-cell measurements, Cu catalysts with high curvature (Cu-HC) exhibit a pronounced positive shift in the volcano-type relationship for C 2+ products. Quantitatively, Cu-HC delivers a 1.36-fold enhancement in C 2+ Faradaic efficiency and a 1.72-fold increase in the C 2+ /C 1 Faradaic efficiency ratio compared with Cu. In situ Raman spectroscopy further underscores the structure-performance correlation induced by curvature engineering, demonstrating that high-curvature surfaces promote the stabilization of *CO intermediates. Density functional theory (DFT) calculations, together with CO electroreduction verification experiments, further indicate that increased surface curvature lowers the energetic barrier for entering C 2+ formation pathways and induces a shift in the reaction route toward the thermodynamically favorable *CO-*CHO coupling mechanism. This study highlights curvature engineering as a general and effective strategy for tuning surface reactivity and promoting the efficient formation of multicarbon products in ECO 2 R. • Establish a curvature-engineered, phase-pure Cu nanoparticle platform that decouples geometric curvature from composition and crystal phase. • Demonstrate that high-curvature Cu catalysts (Cu-HC) significantly enhance C 2+ Faradaic efficiency and the C 2+ /C 1 product ratio in CO 2 electroreduction. • Correlate nanoscale curvature with *CO intermediate stabilization using in situ Raman spectroscopy. • Reveal via DFT and CO electroreduction experiments that increased curvature lowers the barrier for C 2+ pathways and favors an asymmetric *CO–*CHO coupling mechanism. • Propose curvature engineering as a general strategy for tuning surface reactivity and promoting efficient multicarbon product formation in ECO 2 R.