Uniform nickel–cobalt nanoparticles embedded in nitrogen-doped carbon nanofibers for highly active and durable oxygen reduction electrocatalysts

Abstract

Proper design and ingenious preparation of advanced nonnoble metals catalysts with high cost performance and durability for the oxygen reduction reaction (ORR) is in great demand but still full of highly challenges. In this work, nickel-cobalt bimetallic nanoparticles uniformly embedded nitrogen-doped carbon nanofibers (NiCo@NCNFs) have been fabricated through a facile electrospinning technique and followed carbonization process. The Ni-Co nanoparticles are highly dispersed and uniformly embedded in highly conductive nitrogen-doped carbon fibers, providing high specific surface area (640.8 m2 g-1), abundant exposed active sites and easily accessible electronic channels, thus achieving high ORR performance. Specifically, the optimized Ni0.5Co1@NCNFs catalyst exhibits a high onset potential (Eonset = 0.90 V vs RHE) and half-wave potential (E1/2= 0.83 V vs RHE) in an alkaline medium. Moreover, it possessed extraordinary long-term stability and methanol tolerance in comparison to commercial 20% Pt/C catalyst. This simple and cost-effective strategy provides a basis for large-scale production of high-efficiency catalysts that used in various renewable energy systems.