Coral-like Co 3 O 4 Decorated N-doped Carbon Particles as active Materials for Oxygen Reduction Reaction and Supercapacitor.

Coral reef has a unique dendritic structure with large specific surface area, rich pore structure, so that it can be attached to a large number of zooxanthellae for gas exchange. Coral reef ecosystems are also known as underwater rainforests. Inspired by this biological structure, we designed and fabricated coral-like Co3 O4 decorated N-doped carbon particles (Co3 O4 /N-CP). The obtained Co3 O4 /N-CP-900 catalyst shows efficient ORR electrocatalytic performances in an alkaline medium with a positive onset and half-wave potentials of 0.97 and 0.90 V (vs. RHE), as well as a high diffusion-limited current density (5.50 mA cm-2 ) comparable to that of a Pt/C catalyst (5.15 mA cm-2 ). It also displays better stability and methanol tolerance than commercial Pt/C. In addition, the Co3 O4 /N-CP-900 electrode has a high specific capacitance of 316.2 F g-1 in 6 M KOH, as well as good rate capabilities and excellent cycle performance. These results are due to large surface area, narrow pore size distribution, high density electrochemical energy conversion and storage activity centers. This method presented here offers an effective path for the development of high performance multi-functional carbon-based materials for ORR and supercapacitor applications.