Nitrogen-Doped Ketjenblack Carbon Supported Co₃O₄ Nanoparticles as a Synergistic Electrocatalyst for Oxygen Reduction...

Developing a highly active and cost-effective cathode electrocatalyst with strong stability for oxygen reduction reaction (ORR) is extremely necessary. In this work, we reported a facile synthetic path to prepare a hybrid nanostructure formed of nitrogen-doped Ketjenblack carbon (N-KC) supported Co₃O₄ nanoparticles (Co₃O₄/N-KC), which could be used as a promising and stable electrocatalyst for ORR. Compared with the physical mixture of Co₃O₄ and N-KC and pure N-KC samples, the resulting Co₃O₄/N-KC nanohybrid afforded remarkably superb ORR activity with a half-wave potential of 0.82 V (vs. reversible hydrogen electrode, RHE) and a limiting current density of 5.70 mA cm^-2 in KOH solution (0.1 M). Surprisingly, the Co₃O₄/N-KC sample possessed a similar electrocatalytic activity but better durability to the 20 wt% Pt/C catalyst. The remarkable ORR activity of the Co₃O₄/N-KC nanohybrid was mainly due to the strong coupling effect between Co₃O₄ and N-KC, the N species dopant, high electroconductivity, and the large BET surface area. Our work enlightens the exploitation of advanced Co₃O₄/carbon hybrid material alternative to the Pt-based electrocatalysts.