N-doped carbon nanotubes decorated with NiCo alloy nanoparticles: a highly efficient nonprecious metal-based electrocatalyst for ORR

초록

Owing to the severe environmental problems and depletion of fossil fuels, extensive research efforts have been devoted to the development of efficient, clean, and sustainable energy conversion and storage systems. Proton exchange membrane fuel cell (PEMFC) is regarded as promising power source owing to its high conversion efficiency, energy density and environment-friendly advantages. However, the sluggish kinetic behavior of the oxygen reduction reaction (ORR) at the cathode is the main obstacle of PEMFC.[1] Therefore, many researchers have tried to develop the efficient carbon-based hybrid nanomaterials owing to its low cost, outstanding stability, and superior electrochemical activity toward ORR. Herein, we fabricated NiCo alloy nanoparticle encapsulated in N-doped CNT (NiCo-NCNT) using a facile co-precipitation method and high-temperature calcination process.[2] First, NiCo-PBA was prepared via co-precipitation strategy at room temperature for 48hr. After that, the obtained NiCo-PBA was calcined with dicyandiamide (DCD) at 750 °C to synthesize NiCo-NCNT. The synthesized NiCo-NCNT exhibits excellent electrochemical performance with a half-wave potential of 0.827 V vs. RHE for ORR, which is competitive with the commercial Pt/C. The excellent catalytic activity toward ORR of NiCo-NCNT is mainly attributed to synergistic effect between N-doped CNT with high electric conductivity and uniformly distributed NiCo alloy nanoparticle, which can modulate the reaction energy barrier owing to different inherent polarity of the alloy components.[3] We expect this study can provide new inspiration for the design and synthesis of various electrocatalysts.