Key Words:CATALYSTS

Abstract:Developing low-cost and highly efficient electrocatalysts for oxygen reduction reaction (ORR) is a critical challenge in advancing renewable energy technologies, particularly fuel cells and metal-air batteries. This study, for the first time, demonstrates the incorporation of Bi into Fe, N co-doped carbon shells encapsulating Fe3C (Fe3C@Fe/Bi-NC), resulting in enhanced ORR activity. Physical characterizations and theoretical calculations reveal that the incorporation of Bi-O units into the carbon shell along with the core Fe3C nanoparticles comodulate the electronic structure of the Fe-N-C active site, while also increasing the electrochemically active surface area. The Fe3C@Fe/Bi-NC catalyst exhibited a half-wave potential E1/2 of 0.87 V, which is higher than that of Fe3C@Fe-NC (0.84 V), Bi-NC (0.73 V), and the commercial 20 % Pt/C catalyst (0.86 V). Due to the protective carbon shell, Fe3C@Fe/Bi-NC shows good stability with E1/2 shifting negatively by only 24 mV in alkaline and 33 mV in acidic electrolytes after 5000 cycles. Furthermore, the Fe3C@Fe/Bi-NC-based Zn-Air battery achieves a peak power density of 226 mW cm-2 and a high specific capacitance of 801 mAh gZn -1 . The work introduces a novel strategy for engineering core-shell catalysts by modifying the shell structure to significantly improve ORR performance.

Volume:388

Issue:

Translation or Not:no