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Abstract Synthesis of valuable chemicals from CO2 electroreduction in acidic media is highly desirable to overcome carbonation. However, suppressing the hydrogen evolution reaction in such proton-rich environments remains a considerable challenge. The current study demonstrates the use of a hollow fiber silver penetration electrode with hierarchical micro/nanostructures to enable CO2 reduction to CO in strong acids via balanced coordination of CO2 and K+/H+ supplies. Correspondingly, a CO faradaic efficiency of 95% is achieved at a partial current density as high as 4.3 A/cm2 in a pH = 1 solution of H2SO4 and KCl, sustaining 200 h of continuous electrolysis at a current density of 2 A/cm2 with over 85% single-pass conversion of CO2. The experimental results and density functional theory calculations suggest that the controllable CO2 feeding induced by the hollow fiber penetration configuration primarily coordinate the CO2/H+ balance on Ag active sites in strong acids, favoring CO2 activation and key intermediate *COOH formation, resulting in enhanced CO formation.

Carbon dioxide electroreduction driven by renewable electricity into high‐value chemicals enables energy storage while contributing to climate change mitigation. Herein, a CuPd bimetallic catalyst is developed by electrodeposition for efficient CO2 electroreduction, achieving a C2+ Faradaic efficiency as high as 75.6% with a current density of −200 mA cm−2 at −1.15 V versus reversible hydrogen electrode. Upon incorporation of Pd, the average d‐band center of the CuPd bimetallic catalyst downward shifts relative to the Fermi level, making the adsorbed CO intermediates active for further C–C coupling. Theoretical calculations confirm that CO generated on the Pd domain can spill over to the CuPd interface for C–C coupling with a lower energy barrier, further promoting the formation of C2+ compounds. This study provides insights into the rational design of Cu‐based bimetallic catalysts for highly efficient CO2 electroreduction to multicarbon products.

An activated silver hollow fiber electrode enables enhanced triphasic interface reactions and oriented mass transfers synergistically, facilitating efficient CO2 conversion (> 50%) to boost CO production with a current density of 1.26 A · cm−2.