Acid-Alkali Asymmetric Carbon Dioxide-Glycerol Paired Electrolysis for Formate Electrosynthesis

This protocol describes a flow-cell configuration that couples the carbon dioxide electroreduction reaction (CO2RR) at the cathode in acidic media with the glycerol electrooxidation reaction (GOR) at the anode in alkaline media for efficient formate co-production. A dual electrosynthesis system, based on an acid-alkali asymmetric electrolyte design, enhances electron utilization by converting acid-base neutralization energy into a useful electrochemical driving force, thereby promoting formate electro-synthesis. Oxide-derived bismuth nanosheets (OD-Bi NSs) were synthesized via chemical precipitation followed by electroreduction and employed as the cathode catalyst for CO2RR-to-formate conversion. Meanwhile, Co3O4 nanorod catalyst, prepared through chemical precipitation and followed calcination, served as the anode catalyst for Cu²⁺-assisted GOR to formate, where a trace amount of Cu²⁺ brought into the anolyte boosts the GOR activity. The performances, including overpotential, formate selectivity, and activity of OD-Bi NSs and Co3O4 catalysts, were then evaluated in a hybrid electrolyzer. Compared with conventional CO2RR coupled with the oxygen evolution reaction, the CO2RR-GOR paired electrolysis system exhibits significantly reduced power consumption and enhanced formate production.