The Co3O4 hollow dodecahedron (Co3O4@CN) was prepared by calcining ZIF-67 in N2 and then air atmosphere. In the Co3O4@CN compound material, Co3O4 nanoparticles (Co3O4 NPs) are anchored in the carbon skeleton, solving the aggregation problem of Co3O4 NPs. Because Co3O4@CN retains the porous structure of ZIF-67, and the presence of Co2+ and Co3+ favors electron transfer between the enzyme substrates, it has excellent peroxidase-like (POD-like) activity. Enzymatic kinetic tests show that Co3O4@CN has approximately six times more affinity for TMB than HRP and the maximal reaction rate is approximately three times that of HRP. The cholesterol sensor was constructed with Co3O4@CN, and its linear range was 20-1000 μM, and the detection limit was 14.33 μM. The application of Co3O4@CN to the detection of human serum cholesterol will be a valuable research direction.
