Pulsed Electrolysis Promotes CO 2 Reduction to Ethanol on Heterostructured Cu 2 O/Ag Catalysts.

The electrochemical conversion of carbon dioxide (CO 2 ) into ethanol with high added value has attracted increasing attention. Here, an efficient catalyst with abundant Cu 2 O/Ag interfaces for ethanol production under pulsed CO 2 electrolysis is reported, which is composed of Cu 2 O hollow nanospheres loaded with Ag nanoparticles (named as se-Cu 2 O/Ag). The CO 2 -to-ethanol Faradaic efficiency is prominently improved to 46.3% at a partial current density up to 417 mA cm -2 under pulsed electrolysis conditions in a neutral flow cell, notably outperforming conventional Cu catalysts during static electrolysis. In situ spectroscopy reveals the stabilized Cu + species of se-Cu 2 O/Ag during pulsed electrolysis and the enhanced adsorbed CO intermediate ( * CO)coverage on the heterostructured catalyst. Density functional theory (DFT) calculations further confirm that the Cu 2 O/Ag heterostructure stabilizes the * CO intermediate and promotes the coupling of * CO and adsorbed CH intermediate ( * CH). Meanwhile, the stable Cu + species under pulsed electrolysis favor the hydrogenation of adsorbed HCCOH intermediate ( * HCCOH) to adsorbed HCCHOH intermediate ( * HCCHOH) on the pathway to ethanol. The synergistic effect between the enhanced generation of * CO on Cu 2 O/Ag and regenerated Cu + species under pulsed electrolysis steers the reaction pathway toward ethanol. This work provides some insights into selective ethanol production from CO 2 electroreduction via combined catalyst design and non-steady state electrolysis.