In-situ synthesis strategy derived Nitrogen-doped carbon nanotubes embedded with Co nanoparticles active center to inspire oxygen reduction reaction

Abstract

Developing efficient and stable non-precious metal electrocatalysts for oxygen reduction reaction (ORR) is challenging for metal-air batteries. Herein, active sites of Co nanoparticles embedded in nitrogen-doped carbon nanotubes (Co@N-CNTs-800) were prepared by pyrolysis transformation of precursors, using diphenylamine as carbon and nitrogen precursor. It discovered that the abundance of nitrogen species (pyridinic nitrogen and graphitic nitrogen) in the carbon skeleton, the unique carbon nanotube structure, and the synergistic interaction between carbon layers and Co nanoparticles are the main causes for the high ORR catalytic efficiency of the catalysts. As a result, the Co@N-CNTs-800 exhibits powerful electrocatalytic properties for ORR in 0.1 M KOH with half-wave potentials of 0.86 V and an ultimate current density of 5.70 mA cm−2. The zinc-air battery supplied with Co@N-CNTs-800 as the cathode exhibits an exceptional peak power density of 170 mW cm−2 and a specific capacity of 760 mAh gZn−1, demonstrating the enormous potential of novel Co@N-CNTs-800 catalyst in practical applications.