Design and self-assembly of metal-organic framework-derived porous Co3O4 hierarchical structures for lithium-ion batteries

Abstract Porous metal oxides hierarchical structures with controlled morphologies have received great attention because of their promising applications in catalysis, energy storage, gas sensing, etc. Porous Co 3 O 4 hierarchical structures with controlled morphologies were synthesized on the basis of a pyrolytic conversion of Co-based metal-organic frameworks (Co-MOFs), which were initially grown in solutions containing Co(NO 3 ) 2 ·6H 2 O, 1,3,5-Benzentricarboxylic acid and pyrazine as solute and N,N-dimethylformamide (DMF) as solvent under a solvothermal condition. Porous Co 3 O 4 with twin hemispherical and flower-like structures were obtained with the assistance of PVP by adjusting the amount of pyrazine. The results of nitrogen adsorption–desorption indicate the BET surface area (22.6 m 2 g −1 ) of twin hemispherical Co 3 O 4 structures is lower than that (33.3 m 2 g −1 ) of flower-like Co 3 O 4 structures. However, the pore size of twin hemispherical Co 3 O 4 structures is smaller, which is centered at about 2.5, 4.0 and 20.0 nm. The Co 3 O 4 with twin hemispherical structures exhibit more excellent electrochemical performance as anode materials for lithium ion batteries than that of flower-like Co 3 O 4 structures, which may be attributed to the smaller particle size and compact porous structures with suitable pore size.