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 (Fe_xCo_y–N–C), were prepared. The Fe_xCo_y–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–N_x, 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 Fe_xCo_y–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.