Fe/Co Bimetal-Containing Carbon Prepared from a 2D Metalloporphyrin-Based MOF for the Optimal ORR/OER Bifunction and Its Application in Zn–Air Batteries
Zhen Fu, Hongyan Zhuo, Xue Liu, Wenjuan Li, Hao Song, Zhuang Shi, Linlin Feng, Tenglong Jin, Wenmiao Chen, Yanli Chen
Abstract
The Fe–N 4 -based Fe single-atom catalyst exhibits high efficiency in oxygen reduction reaction (ORR) activity, while Co oxides demonstrate excellent oxygen evolution reaction (OER) activity. In this study, we report an easily synthesized carbon-based catalyst CoFe@CNT that incorporates both Fe single atoms and CoO nanoparticles. This catalyst is derived from a two-dimensional metalloporphyrin-based metal–organic framework (CoFeMOF) composed of an FeTCPP (5,10,15,20-tetrakis(p-carboxylphenyl)porphyrin iron) building unit coordinated with Co 2+ and 4,4′-bipyridine. CoFe@CNT exhibits superior ORR (half-wave potential = 0.85 V) and OER (overpotential at 10 mA cm –2 = 370 mV) performances and better stability compared to both ZnFe@CNT and Co@CNT (from the respective ZnFeMOF and CoMOF precursors) and commercial Pt/C catalysts. XPS analysis reveals that the presence of both Fe–N 4 single-atom and CoO nanoparticles in CoFe@CNT not only induces electron transfer from Co to Fe but also generates a higher combined content of pyridinic N and Fe–N 4 compared to both ZnFe@CNT and Co@CNT, which enhances the catalytic activity. A Zn–air battery using CoFe@CNT as the cathode catalyst achieves a high power density (115 mW cm –2 ), outperforming the Pt/C catalyst. The design and synthesis of this 2D MOF-derived electrocatalyst offer promising prospects for developing high-density metal–air batteries.