Metal-organic framework as a host for synthesis of nanoscale Co3O4 as an active catalyst for CO oxidation

Co3O4 nanoparticles were prepared from cobalt nitrate that was accommodated in the pores of a metal-organic framework (MOF) ZIF-8 (Zn(MeIM)2, MeIM = 2-methylimidazole) by using a simple liquid-phase method. The ZIF-8 host was removed by pyrolysis under air and subsequently washing with an NH4Cl–NH3·H2O aqueous solution. Transmission electron microscopy (TEM) analysis shows that the obtained Co3O4 is composed of separate nanoparticles with a mean size of 18 nm. The Co3O4 nanoparticles exhibit excellent catalytic activity, cycling stability, and long-term stability in the low temperature CO oxidation.

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► Pyrolysis of cobalt nitrate confined in the pore of a MOF yields nanoscale Co3O4.
► The MOF host is fully removed to yield neat Co3O4.
► The Co3O4 is composed of separate nanoparticles with a uniform size of ca. 18 nm.
► The Co3O4 exhibits excellent catalytic activity and stability in CO oxidation.