Noble metal-based electrocatalysts are the key materials to promote the technical development of fuel cells and metal-air batteries. However

the single catalytic function towards oxygen reduction/oxygen evolution and the prohibitive cost restrict their extensive application. Therefore

it is of great significance to develop non-noble metal-based bi-functional electrocatalysts with low-cost and high-efficiency. In this study

taking core-shell metal organic frameworks (MOFs) as precursors

cobalt/nitrogen co-doped carbon-based electrocatalyst (Co/Co3O4@NGC) was fabricated using high-temperature calcination technology

with a core-shell structure

high catalytic activity

and high conductivity. Results show that the calcination temperature was the key factor affecting the micro-nano structure

physicochemical composition

and catalytic activity of the electrocatalyst. The optimal temperature of calcination was 900 ℃. The fabricated electrocatalyst (Co/Co3O4@NGC-900) had a clear core-shell structure and 3D-dodecahedron morphology with Co/Co3O4 nanoparticles and Co-Nx sites on its micro-surface. In addition

Co/Co3O4@NGC-900 inherently combined the synergistic effects of both multiple active ingredients (e.g.

active Co/Co3O4 nanoparticles

Co-Nx

and N dopants) and highly graphitized carbon substrates

and thus exhibited efficient oxygen reduction performance (ORR

onset potential of 0.89 V

half-wave potential of 0.82 V

Tafel slope of 58.1 mV/dec

and charge transfer resistance of 26.6 Ω) and oxygen evolution performance (OER

overpotential of 410 mV

Tafel slope of 132 mV/dec

and charge transfer resistance of 24.5 Ω). Therefore

Co/Co3O4@NGC-900 exerted electrocatalytic performance comparable to that of typical noble metal-based electrocatalysts (e.g.

Pt/C

RuO2/C)

and achieved significant reduction of catalyst fabrication cost on the premise of ensuring its high-efficient electrocatalytic activity

providing theoretical and technical support for the fabrication and application of innovative MOFs derived electrocatalytic materials.