Solvent effect to modulate nitrogen dopant in Co-N-C catalysts for oxygen reduction reaction acceleration

• Published in: Fuel (Guildford) 2023-08, Vol.345, p.128199, Article 128199
• Main Authors: Li, Lingfeng, Han, Guokang, Wen, Yandi, Liu, Yuxin, Xiao, Rang, Zhang, Wei, Kong, Fanpeng, Du, Lei, Ma, Yulin, Zuo, Pengjian, Du, Chunyu, Yin, Geping
• Format: Article
• Language: English
• Subjects: Co-N-C; Metal-organic frameworks; Oxygen reduction reaction; Pyridinic nitrogen dopant; Solvent effect
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2023.128199

[Display omitted] •The content of pyridinic N in Co-N-C catalysts is modulated via solvent effect.•DFT calculations reveal that the synergy of pyridinic-N and CoNx significantly accelerate the ORR.•The content of pyridine N in the prepared atomically dispersed Co-N-C catalyst is up to 43.7%.•The optimal Co-N-C catalyst exhibits high ORR activity in acid media. Rational design of platinum group metal (PGM)-free catalysts, e.g., M−N−C catalysts, with well-defined structure is highly essential to replace the conventional PGM-based catalysts towards oxygen reduction reaction (ORR), which, however, is still challenging. Particularly, extra nitrogen plays an important role in the ORR performance of M−N−C but the mechanism remains unclear. In this work, a facile modulation strategy based on solvent effect is proposed to tailor nitrogen dopants in the metal organic frameworks (MOFs)-derived Co-N-C catalysts. DFT calculations reveal that the synergy of pyridinic-N and CoNx significantly accelerate the ORR. Reasonably, the optimized Co-N-C catalyst shows superior onset potential (Eonset) of 0.915 V and half-wave potential (E1/2) of 0.785 V toward ORR. This work may pave an avenue for the precise construction of active moieties in large-scale preparation of PGM-free ORR catalyst.