Asymmetric C–C Coupling Driven by Heterostructured Ag–Bi Electrocatalyst Enables Selective CO 2 Reduction to Ethanol for Microbial Growth

ABSTRACT Electrocatalytic CO 2 reduction (eCO 2 RR) coupled with microbial fermentation offers a promising route for carbon valorization, but faces dual challenges from toxic C 1 byproducts (e.g. formate) and poor long‐term catalytic stability. Herein, we present a heterostructured Ag–Bi electrocatalyst (Ag 1.65 @Bi 2 O 3 ) with interfacial synergy that drives asymmetric C–C coupling, enabling highly selective conversion of CO 2 to ethanol with a Faradaic efficiency of 87.00% and stable operation for 324 h at ‐0.9 V vs RHE. In situ Fourier transform infrared spectroscopy and density functional theory calculations further reveal an asymmetric coupling pathway between *CO and *CHO intermediates, thereby reducing the C–C coupling energy barrier for ethanol production. The obtained liquid stream exhibits no formate toxicity and can be directly utilized by Saccharomyces cerevisiae in an integrated electrochemical‐microbial system for yeast production with a yield of 1.05 ± 0.04 g L −1 , which is 35% higher than that of the single fermentation system. This study provides a paradigm for realizing a coupling system of eCO 2 RR and microbial fermentation.