Iron carbide encapsulated by porous carbon nitride as bifunctional electrocatalysts for oxygen reduction and evolution reactions

• Published in: Applied surface science 2018-05, Vol.439, p.439-446
• Main Authors: Wei, Liangqin, Sun, Hongdi, Yang, Tiantian, Deng, Shenzhen, Wu, Mingbo, Li, Zhongtao
• Format: Article
• Language: English
• Subjects: Electrocatalyst; Metal organic frameworks; Metal-air battery; Oxygen evolution reaction; Oxygen reduction reaction
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2018.01.056

[Display omitted] •Fe3C/carbon nitride core-shell structure composites were available through pyrolysis a coordination compound.•Optimized catalyst exhibited excellent ORR and OER electrocatalytic activity comparable to Pt/C.•Synergetic effect of strong coupling between Fe3C and nitrogen doped carbon shells to achieve superior catalytic performance. Herein, the study reports a facile and scale-up able strategy to synthesize metal organic frameworks (MOFs) Fe-7,7,8,8-Tetracyanoquinodimethane (Fe-TCNQ) as precursors to develop non-precious metal bifunctional electrocatalysts through a one-step hydrothermal route. Then, Fe3C/carbon nitride (Fe3C@CNx) core-shell structure composites are readily available through pyrolyzing Fe-TCNQ at reasonable temperature, during which hierarchical porous structures with multimodal porosity formed. Nitrogen doped porosity carbon layers can facilitate mass access to active sites and accelerate reaction. Consequently, the optimized catalyst exhibits superior oxygen reduction reaction (ORR) electrocatalytic activity and better catalytic activity for oxygen evolution reaction (OER) in alkaline medium than that of Pt/C, which can be attributed to the synergistic effect of strong coupling between Fe3C and nitrogen doped carbon shells, active sites Fe-NX, optimal level of nitrogen doping, and appropriate multimodal porosity.