Co-Co3O4@carbon core-shells derived from metal-organic framework nanocrystals as efficient hydrogen evolution catalysts

Controllable pyrolysis of metal-organic frameworks (MOFs) in confined spaces is a promising strategy for the design and development of advanced functional materials. In this study, Co-Co3O4@carbon composites were synthesized via pyrolysis of a Co-MOFs@glucose polymer (Co-MOFs@GP) followed by partial oxidation of Co nanoparticles (NPs). The pyrolysis of Co-MOFs@GP generated a core-shell structure composed of carbon shells and Co NPs. The controlled partial oxidation of Co NPs formed Co-Co3O4 heterojunctions confined in carbon shells. Compared with Co-MOFs@GP and Co@carbon-n (Co@C-n), Co-Co3O4@carbon-n (Co-Co3O4@C-n) exhibited higher catalytic activity during NaBH4 hydrolysis. Co-Co3O4@C-II provided a maximum specific H-2 generation rate of 5,360 mL.min(-1).g(Co)(-1) at room temperature due to synergistic interactions between Co and Co3O4 NPs. The Co NPs also endowed Co-Co3O4@C-n with the ferromagnetism needed to complete the magnetic momentum transfer process. This assembly-pyrolysis-oxidation strategy may be an efficient method of preparing novel nanocomposites.