Surface-oxidized Fe-Co-Ni alloys anchored to N-doped carbon nanotubes as efficient catalysts for oxygen reduction reaction

摘要

Developing a cheap, efficient, and stable oxygen reduction reaction (ORR) catalyst for fuel cells has the potential to help address the energy crisis. This work reports low-cost ternary transition metal alloy nanoparticles anchored to nitrogen-doped carbon nanotubes (N-CNTs), i.e., Fe2Co2Ni2/N-CNTs, as an efficient ORR catalyst. The ORR performance of this ternary metal-based catalyst was found to be better than that of binary metal-based catalysts. The non-uniformities in the metal oxide layer, formed on the surface of the alloy particles, provided more ORR active sites. This novel core-shell structure of the alloy particles allowed Fe2Co2Ni2/NCNTs to catalyze ORR efficiently. This catalyst exhibits an onset potential of 0.811 V vs RHE, a half-wave potential of 0.749 V vs RHE, and a limiting current density of 5.28 mA cm(-2) for ORR, which is close to commercial Pt/C and most previously reported catalysts. Notably, Fe2Co2Ni2/N-CNTs exhibits better stability and resistance to methanol than Pt/C catalysts. These results indicate that the catalysts based on ternary transition metal alloy nanoparticles anchored to carbon materials have great potential for storage and transformation of clean energy. (C) 2020 Elsevier B.V. All rights reserved.