Controlling the local electronic structure of active ingredients to improve the adsorption-desorption characteristics of oxygen-containing intermediates over the electrochemical liquid-solid interfaces is a critical challenge in the field of oxygen reduction reaction (ORR) catalysis. Here, we offer a simple approach for modulating the electronic states of metal nanocrystals by bimetal co-doping into carbon-nitrogen substrate, allowing us to modulate the electronic structure of catalytic active centers. To test our strategy, we designed a typical bimetallic nanoparticle catalyst (Fe-Co NP/NC) to flexibly alter the reaction kinetics of ORR. Our results from XAS (synchrotron X-ray absorption spectroscopy) and XPS (X-ray photoelectron spectroscopy) showed that the co-doping of iron and cobalt could optimize the intrinsic charge distribution of Fe-Co NP/NC catalyst, promoting the oxygen reduction kinetics and ultimately achieving remarkable ORR activity. Consequently, the carefully designed Fe-Co NP/NC exhibits an ultra-high kinetic current density at the operating voltage (71.94 mA cm-2 at 0.80 V), and the half-wave potential achieves 0.915 V, which is obviously better than that of the corresponding controls. Our findings provide a unique perspective for optimizing the electronic structure of active centers to achieve higher ORR catalytic activity and faster kinetics.
