Polyaniline Encapsulated Cu Nanowires Steering *CO Adsorption Configuration to Enhance Ethanol Selectivity in CO2 Electrocatalysis.

Electrocatalytic CO2 reduction (CO2RR) to liquid ethanol has emerged as a critical research direction. Ethanol, which undergoes the same C─C coupling process but requires more proton-coupled electron transfer (PCET) steps than ethylene, which makes the enhancement of ethanol selectivity a significant challenge. Herein, polyaniline-encapsulated Cu Nanowires (Cu@PANI-5) have been synthesized via a self-assembly strategy. The Cu@PANI-5 with a 5 nm PANI shell achieves 80% multi-carbon product selectivity and 42% ethanol Faradaic efficiency at 400 mA cm-2 current density. In situ spectroscopy measurements and density functional theory calculations demonstrate that the PANI modification can regulate the *CO intermediate adsorption configuration from *COtop to *CObridge on the Cu NWs interface, thereby effectively accelerates the PCET process of CO2RR. When the ratio of *COtop to *CObridge is regulated to 1:3 by modulating the thickness of the PANI shell, the C─C coupling is most favorable. The balanced C─C coupling and PCET hydrogenation processes under this ratio enhance the selectivity of ethanol. This work highlights that the *CO intermediate adsorption configuration is pivotal for CO2RR catalytic performance, providing valuable guidance for optimizing ethanol selectivity.