Metal

Catalysis

Oxygen evolution

Adsorption

Composite number

Engineering

Nanoparticle

Mesoporous material

Pyrolysis

Electrochemistry

Metallurgy

Materials science

Carbon fibers

Inorganic chemistry

Chemical engineering

Electrocatalyst

Porosity

Physical chemistry

Microporous material

Nanotechnology

Organic chemistry

Oxygen

Doping

Metal-organic framework

Composite material

Cobalt

Chemistry

Electrode

Optoelectronics

Bifunctional

Specific surface area

Applied Surface Science

Metal-organic frameworks (MOFs) materials have aroused great research interest in different areas owing to their unique properties, such as high surface area, various composition, well-organized framework and controllable porous structure. Controllable fabrication of MOFs materials at macro-scale may be more promising for their large-scale practical applications. Here we report the synthesis of macro-scale Co-MOFs crystals using 1,3,5-benzenetricarboxylic acid (H3BTC) linker in the presence of Co2+, triethylamine (TEA) and nonanoic acid by a facile solvothermal reaction. Further, the as-fabricated Co-MOFs as precursor was pyrolytically treated at different temperatures in N2 atmosphere to obtain metallic Co nanoparticles embedded in N-doped porous carbon layers (denoted as [email protected]). The results demonstrate that the Co-MOFs derived sample obtained at 900 °C ([email protected]) shows a porous structure (including micropore and mesopore) with a surface area of 110.8 m2 g−1 and an N doping level of 1.62 at.% resulted from TEA in the pyrolysis process. As electrocatalyst, the [email protected] exhibits bifunctional electrocatalytic activities toward the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline media which are key reactions in some renewable energy technologies such as fuel cells and rechargeable metal-air batteries. The results indicate that the [email protected] can afford an onset potential of 1.50 V (vs. RHE) and a potential value of 1.61 V (vs. RHE) at a current density of 10 mA cm−2 for ORR and OER with high applicable stability, respectively. The efficient catalytic activity of [email protected] as bifunctional oxygen electrocatalyst can be ascribed to N doping and embedded metallic Co nanoparticles in carbon structure providing catalytic active sites and porous structure favourable for electrocatalysis-related mass transport.

Macroscale cobalt-MOFs derived metallic Co nanoparticles embedded in N-doped porous carbon layers as efficient oxygen electrocatalysts