Upgrading CO₂ into acetate on Bi₂O₃@carbon felt integrated electrode via coupling electrocatalysis with microbial synthesis

Abstract Upgrading of atmospheric CO 2 into high‐value‐added acetate using renewable electricity via electrocatalysis solely remains a great challenge. Here, inspired by microbial synthesis via biocatalysts, we present a coupled system to produce acetate from CO 2 by bridging inorganic electrocatalysis with microbial synthesis through formate intermediates. A 3D Bi 2 O 3 @CF integrated electrode with an ice‐sugar gourd shape was fabricated via a straightforward hydrothermal synthesis strategy, wherein Bi 2 O 3 microspheres were decorated on carbon fibers. This ice‐sugar gourd‐shaped architecture endows electrodes with multiple structural advantages, including synergistic contribution, high mass transport capability, high structural stability, and large surface area. Consequently, the resultant Bi 2 O 3 @CF exhibited a maximum Faradic efficiency of 92.4% at −1.23 V versus Ag/AgCl for formate generation in 0.5 M KHCO 3 , exceeding that of Bi 2 O 3 /CF prepared using a conventional electrode preparation strategy. Benefiting from the high formate selectivity, unique architecture, and good biocompatibility, the Bi 2 O 3 @CF electrode attached with enriched CO 2 ‐fixing electroautotrophs served as a biocathode. As a result, a considerable acetate yield rate of 0.269 ± 0.009 g L −1 day −1 (a total acetate yield of 3.77 ± 0.12 g L −1 during 14‐day operation) was achieved in the electrochemical–microbial system equipped with Bi 2 O 3 @CF.