Cu2O@Co/N-doped carbon as antibacterial catalysts for oxygen reduction in microbial fuel cells

Abstract

Biofouling and sluggish kinetics on the cathode surface reduce the power generation of microbial fuel cells (MFCs). In this work, ZIF-derived Cu₂O@Co/N-doped carbon (Cu₂O@Co/NC) was used as an antibacterial oxygen reduction reaction (ORR) catalyst for MFCs. As an antibacterial agent on the cathode surface, Cu₂O can inhibit the excessive growth of biofilms, facilitate the diffusion of OH⁻ ions, and reduce the electron transfer resistance in ORR. The interaction between Cu₂O and Co/NC was studied by charge density analysis. Charge redistribution can promote the adsorption of O₂ molecules, resulting in enhanced ORR activity. The Cu₂O@Co/NC cathode demonstrated superior ORR activities due to a half-wave potential of 0.80 V and an onset potential of 0.89 V versus RHE. The corresponding MFCs gained a maximum power density of 1100 mW m⁻² after 450 h of operation, which was higher than that of Co/NC (739 mW m⁻²) and similar to that of commercial Pt/C (1067 mW m⁻²). Our work provides a strategy to achieve high power density of MFCs by combining the advantages of Cu₂O and Co/NC catalysts.