Alliance of atomic-scale/nanoscale Fe/Co active sites with hierarchically porous N-doped carbon frameworks for efficient electrocatalytic oxygen reduction

• Published in: Rare metals 2023-11, Vol.42 (11), p.3766-3779
• Main Authors: Yang, Hai-Hua, Qian, Xiao-Rong, Zhang, Na, Jia, Xia-Ting, Wen, Zhi-Yan, Chen, Xiao-Bo, Zhou, Min-Jie
• Format: Article
• Language: English
• Subjects: Biomaterials; Carbon; Carbon nitride; Catalytic activity; Chemical reduction; Chemistry and Materials Science; Cobalt; Durability; Electrical resistivity; Electrocatalysts; Energy; Intermetallic compounds; Iron; Mass transport; Materials Engineering; Materials Science; Metal air batteries; Metallic Materials; Nanoscale Science and Technology; Nitrogen; Original Article; Oxygen reduction reactions; Physical Chemistry; Transition metals; Zinc-oxygen batteries
• ISSN: 1001-0521; 1867-7185
• DOI: 10.1007/s12598-023-02397-8

Ingenious establishment of transition metal–nitrogen–carbon electrocatalysts with diverse catalytic active sites and hierarchically porous frameworks is highly significant to boost the oxygen reduction reaction (ORR) in Zn–air batteries (ZABs). In this study, Fe/Co co-doped zeolitic imidazolium frameworks (ZIFs) and graphitic carbon nitride (g-C 3 N 4 ) were integrated and pyrolyzed to construct carbon-based electrocatalysts containing Fe, Co and N elements (labelled as Co–CoFe@NRPC), in which atomic-scale FeN x and CoN x , and nanoscale metallic Co and CoFe alloy moieties were aligned with hierarchically porous N-doped carbon frameworks constructed by interconnected micropolyhedrons, nanotubes and nanosheets. The diverse active moieties guaranteed excellent intrinsic catalytic activity, while the hierarchically porous N-doped carbon frameworks ensured admirable accessibility of the catalytic active sites, excellent electrical conductivity, satisfactory mass transport and good durability. Expectedly, the optimized Co–CoFe@NRPC-90 (with 90 mg g-C 3 N 4 added) electrocatalyst exhibited excellent ORR performance with a high half-wave potential of 885 mV (vs. reversible hydrogen electrode (RHE)), diffusion-limiting current density of 6.15 mA·cm −2 , desirable durability and methanol tolerance. Simultaneously, the liquid ZAB established with Co–CoFe@NRPC-90 as an air–cathode electrocatalyst manifested an outstanding power density (281 mW·cm −2 ) and specific capacity (820.9 mAh·g Zn −1 ), transcending the liquid ZAB based on a commercial Pt/C electrocatalyst. Graphical abstract