Chalcogen-Modified Copper-Nitrogen Co-Doped Carbon as a Stable and Efficient Antimicrobial Cathode Catalyst for Microbial Fuel Cells

Microbial fuel cell (MFC) is attracting attention for its ability to electricity generation and wastewater treatment. The slow oxygen reduction reaction (ORR) kinetics and biofilm contamination of the cathode severely degrade the performance of the MFC. Herein, a series of chalcogen-modified copper and nitrogen co-doped catalysts Cu2X@Cu-XNC-x (X=S or Se, x=1, 2 and 3) were obtained successfully by sulfidation or selenization using MOF as the precursor. It was found that proper doping of chalcogen (such as S and Se) could effectively improve the ORR performance of Cu-N-C while maintaining the antibacterial properties. Among these catalysts, the optimum Cu2S@Cu-SNC-2 catalyst displayed excellent durability and ORR activity with a half-wave potential of 0.73 V vs. RHE in neutral solution, which was significantly better than the commercial 20% Pt/C (0.70 V vs. RHE). As a result, the maximum power density of the MFC based on Cu2S@Cu-SNC-2 reached 904 ± 25 mW m-2, which was much better than that using commercial 20% Pt/C (477 ± 22 mW m-2). In addition, the MFC assembled with Cu2S@Cu-SNC-2 possessed less cathode biofilm after the operation, which was beneficial for long-term stability. The present work may provide a new approach to developing an efficient and stable antimicrobial cathode catalyst for MFC.