Efficient bio-electroreduction of CO2 to formate on a iron phthalocyanine-dispersed CDC in microbial electrolysis system

Bio-electroreduction of CO2 to formate is carried out in a double-chambered microbial electrolysis system (MES) using the iron phthalocyanine (FePc) dispersed carbide-derived carbon (CDC) cathode. Formate dehydrogenase (FDH) released by prokaryotic E. coli catalyzes the CO2 reduction and acts as a promotor for selective formate generation. The prepared FePc-CDC composite catalyst is characterized by several physico- and electro-chemical characterization techniques including scanning electron microscopy, surface area analysis, X-ray diffraction, and infrared spectroscopy to corroborate the sustainability of as-synthesized catalyst material in MES. The FePc-CDC-based MES shows a maximum formate production rate of similar to 30 mg/L.h from CO2 (120 mg/L.h) at a poised potential of similar to 1.0 V (Ag/AgCl) using E. coli and neutral red mediator. The study clearly demonstrates that the electrofermentation of CO2 to formate in a FePc-CDC cathode-based MES can be a selective and viable green process for the utilization of CO2 as a sole carbon feed-stock. (C) 2020 Elsevier Ltd. All rights reserved.