Boosting activity toward the oxygen reduction reaction of a hyper-crosslinked FeCu bimetal nanocatalyst via mimicking cytochrome c oxidase

Abstract

The sluggish oxygen reduction kinetics and prohibitive noble metal dependency constitute critical bottlenecks in fuel cell commercialization. Herein, by simulating the active center components and the Fe–N₄ microstructure of cytochrome c oxidase (CcO), a novel Fe–Cu bidentate site catalyst was successfully prepared. This catalyst is embedded in a super-cross-linked N-doped carbon framework (FeCu@NC). Research shows that the measured half-wave potential (E_1/2) of FeCu@NC under alkaline conditions is 0.89 V, surpassing that of Pt/C, and showed a positive shift of 40 mV, and the oxygen reduction kinetics were enhanced, while maintaining 92.7% current retention after 20 000 s chronoamperometric testing. The combination of experimental data and theoretical calculations reveals that the superior performance of this catalyst can be attributed to the synergistic catalytic effect exhibited by the dual functions of copper and iron. This characteristic is in line with the design concept of CcO. During this process, copper metal acts as an electron donor, and the unique synergy between copper and the FeN₄ center significantly enhances the electron density, thereby effectively promoting the reduction reaction of oxygen.