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.
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