Electron‐Efficient Formate Electrosynthesis from CO ₂ and Biomass‐Derived Carbohydrates in a Zero‐Gap Electrolyzer

Abstract

ABSTRACT Paired electrolysis is being actively developed for co‐producing valuable chemicals by leveraging electron transfer at bipolar electrodes. In electrochemical CO 2 reduction to formate, if the reaction is coupled with oxygen evolution reaction, formate experiences severe crossover and oxidation to CO 2 over anode in membrane electrode assembly (MEA) electrolyzer. We reported a convergent electrolysis that produces formate at bipolar electrodes by coupling CO 2 reduction with biomass‐derived carbohydrate (for example, glucose) oxidation, maximizing the electron efficiency toward formate (0.88 formate per e − ) and suppressing oxidation of crossed formate at anode. This convergent electrolysis shows low electricity consumption for formate production (76.5 Wh mol −1 at 100 mA cm −2 ), lower than that of conventional CO 2 reduction (180−350 Wh mol −1 ). Furthermore, we extended the convergent electrolysis to acetate production by coupling electrochemical CO reduction with waste polylactic acid plastic oxidation. This work offers a framework for the rational design of paired electrolysis for low electricity consumption of chemical production.