A co-doped oxygen reduction catalyst with FeCu promotes the stability of microbial fuel cells

Air cathode microbial fuel cell (AC-MFC) cannot be used on a large scale because of its low oxygen reduction reaction (ORR) efficiency. Despite the fact that bimetallic catalysts can greatly enhance the oxygen reduction rate by regulating the electronic structure of the active site, the flaws of insufficient exposure of the active site and easy metal agglomeration limit its catalytic activity. Herein, we report on the preparation of a stable heteroatomic substrate using a copper material organic framework as a precursor, covered by Fe-based active sites. As a result of dipole-dipole interactions, the reduced product Fe²⁺ forms a weak Fe-O surface that is conducive to the adsorption of active substances. The presence of Fe⁰ enhances the electrical conductivity of the catalytic, thus promoting ORR efficiency. Through redox coupling, the D-band center of Fe at FeCu@CN is optimized and brought close to the Fermi level to facilitate electron transfer. Notably, FeCu@CN demonstrates a superior power density of 2796.23 ± 278.58 mW m^-3, far exceeding that of Pt/C (1363.93 ± 102.56 mW m^-3), in the application of microbial fuel cells (MFCs). Meanwhile, the MFC-loaded FeCu@CN maintains excellent stability and outstanding output voltage after 1000 h, which provides feasibility for large-scale application.