Metal-organic-framework-derived bimetallic carbon-based catalysts as efficient oxygen reduction reaction electrocatalysts

Abstract

The sluggish kinetics of oxygen reduction reaction (ORR) as well as costly production of current Pt/C catalysts limit the practical application of Zn-air battery (ZAB). It is challenging to synthesize an ideal ORR catalyst with intriguing features, including a conductive network, a directed pathway for charge transfer, and abundant active sites such as bimetallic alloy nanoparticles. In this work, FeCo alloys are successfully combined due to the uniform distribution of encapsulated Fe and surface-bound Co by means of electrospinning and pyrolysis. As a result, the prepared FeCo/N-CNFs have an exceptional ORR performance (E1/2 = 0.88 V, j = 5.20 mA cm−2) that considerably outperforms Pt/C (E1/2 = 0.85 V, j = 4.75 mA cm−2). In addition, ZAB based on FeCo/N-CNFs display a superior peak power density (356.23 mW cm−2) than Pt/C-ZAB (299.29 mW cm−2). The high degree of graphitization from FeCo alloy nanoparticles, the directed charge transfer channel from a one-dimensional nanofiber structure, and the interaction between M-NX and pyridine N/graphite N species all contribute to the exceptional electrocatalytic performance.