Activated carbon supported Fe–Cu–NC as an efficient cathode catalyst for a microbial fuel cell

Abstract

Microbial fuel cell (MFC) is a promising device for converting bioenergy into electrical energy, but its performance is mainly limited by the slow kinetics of the oxygen reduction reaction (ORR). Hence, exploring ORR catalysts with low cost and great performance is of great practical significance for improving the power generation efficiency of MFCs. In this study, we prepared an electrocatalyst of an Fe–Cu–N multi-doped carbon matrix through pyrolyzing Fe–Cu Prussian blue analogs (PBA) under the protection of nitrogen. Fe–Cu–NC with high activity bimetallic active sites efficiently optimized the electronic distribution of the Fe–Cu–N multi-doped carbon matrix and thereby improved the ORR activity. Electrochemical analysis indicated that the Fe–Cu–N multi-doped carbon structure exhibited excellent ORR catalytic activity and stability. Therefore, MFCs with an Fe–Cu–NC-50% catalyst offered an output power density up to 413.01 mW m⁻², which was 3.5 times higher than that of the control (116.16 mW m⁻²). Besides, using Fe–Cu–NC-50% as an ORR catalyst, a chemical oxygen demand (COD) removal ratio of about 81.62 ± 3.48% was obtained. This work indicates that the synthesized Fe–Cu–N multi-doped carbon structure will have a promising future in the practical application of MFCs.