FeCo nanoalloys embedded in nitrogen-doped carbon nanosheets/bamboo-like carbon nanotubes for the oxygen reduction reaction

Abstract

Herein, FeCo bimetallic organic frameworks (MOFs) with different compositions were fabricated by controlling the initial molar ratio of Fe3+/Co2+ ions. Through a one-step carbonization treatment of FeCo MOFs and the melamine mixture, a series of FeCo nanoalloys encapsulated in bamboo-like N-doped carbon nanotubes (CNTs), entangled with N-doped carbon nanosheet nanocomposites (FexCoy-N-C), were prepared. The FexCoy-N-C materials presented an excellent ORR performance in alkaline medium. X-ray photoelectron spectroscopy (XPS) studies revealed the existence of ORR-active centers, such as Co-Nx, pyridinic-N and graphitic-N, which were responsible for the enhanced ORR activity. Besides, the synergistic coupling between FeCo alloy and N-doped carbon nanotubes favors the enhancement of the electrocatalytic performance. Among FexCoy-N-C electrocatalysts, the optimized Fe1Co3-N-C and Fe3Co1-N-C catalysts showed higher ORR performance. In addition, both Fe1Co3-N-C and Fe3Co1-N-C showed superior stability compared to the benchmark commercial Pt/C catalyst.