Highly Selective Production of C₂₊ Oxygenates from CO₂ in Strongly Acidic Condition by Rough Ag‐Cu Electrocatalyst

The acidic electrocatalytic conversion of CO 2 to multi‐carbon (C 2+ ) oxygenates is of great importance in view of enhancing carbon utilization efficiency and generating products with high energy densities, but suffering from low selectivity and activity. Herein, we synthesized Ag−Cu alloy catalyst with highly rough surface, by which the selectivity to C 2+ oxygenates can be greatly improved. In a strongly acidic condition (pH=0.75), the maximum C 2+ products Faradaic efficiency (FE) and C 2+ oxygenates FE reach 80.4 % and 56.5 % at −1.9 V versus reversible hydrogen electrode, respectively, with a ratio of FE C2+ oxygenates to FE ethylene up to 2.36. At this condition, the C 2+ oxygenates partial current density is as high as 480 mA cm −2 . The in situ spectra, control experiments and theoretical calculations indicate that the high generation of C 2+ oxygenates over the catalyst originates from its large surface roughness and Ag alloying.