Nitrogen-Doped Ketjenblack Carbon Supported CoO Nanoparticles As a Synergistic Electrocatalyst for Oxygen Reduction Reaction

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 CoO nanoparticles (CoO/N-KC), which could be used as a promising and stable electrocatalyst for ORR. Compared with the physical mixture of CoO and N-KC and pure N-KC samples, the resulting CoO/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 in KOH solution (0.1 M). Surprisingly, the CoO/N-KC sample possessed a similar electrocatalytic activity but better durability to the 20 wt% Pt/C catalyst. The remarkable ORR activity of the CoO/N-KC nanohybrid was mainly due to the strong coupling effect between CoO and N-KC, the N species dopant, high electroconductivity, and the large BET surface area. Our work enlightens the exploitation of advanced CoO/carbon hybrid material alternative to the Pt-based electrocatalysts.