CO ₂ electroreduction to acetate by enhanced tandem effects of surface intermediate over Co ₃O ₄ supported polyaniline catalyst

Among the numerous CO₂ electroreduction reactions to produce chemicals, the reaction to generate ccaetate products is an extremely important and widely studied reaction. Here, we report a heterogeneous catalyst with Co₃O₄nanoparticles immobilized on polyaniline (PANI) and co-supported by highly graphitized carbon (Co₃O₄/PANI/C) for electroreduction of CO₂ to acetate with high activity and selectivity. A remarkably enhanced acetate Faraday efficiency (~ 62 %) and current density (~ 35 mA/cm²) has been obtained under conditions of static electroreduction at -0.95 V in 0.5 M KOH aqueous electrolyte, while the HER is suppressed at the same time. Its excellent performance is attributed to the tandem effects between the Co₃O₄ nanoparticles with abundant oxygen vacancy and the PANI heterogeneous interface in a favorable configuration. Theoretical DFT calculations have revealed that the tandem configuration of Co₃O₄/PANI/C facilitates the rapid delivery of the key intermediate *CO formed on Co₃O₄ to PANI, resulting in increased surface intermediate *CO coverage on the catalyst, and promotes acetate production during CO₂ reduction reaction.