ZIF-derived Co3O4/Fe2O3 dual-layer hollow nanoboxes as bimetallic nanozymes for detection of hydrogen peroxide and ascorbic acid

Abstract

Nanozymes, owing to their high stability and cost-effectiveness, present themselves as appealing alternatives to natural enzymes. The rational design of complex metal–organic framework (MOF) hybridization precursors offers significant opportunities for constructing diverse functional nanostructures. This paper introduces a novel strategy, assisted by MOF hybridization, for synthesizing Co₃O₄/Fe₂O₃ dual-layer hollow nanoboxes (DLHNBs) via anion exchange, coupled with low-temperature pyrolysis, employing ZIF-67 as the original template. This approach maximizes the advantages of hollow nanostructures, functioning as both nanoreactors and substrate channels, thereby mimicking the action of natural enzymes. The Co₃O₄/Fe₂O₃ DLHNBs exhibited lower steady-state kinetic parameters, indicating a superior affinity between Co₃O₄/Fe₂O₃ DLHNBs and H₂O₂. Furthermore, the sensing application of Co₃O₄/Fe₂O₃ DLHNBs nanozymes for the determination of H₂O₂ and ascorbic acid (AA) was explored by using a colorimetric method. The linear range for H₂O₂ detection was established at 100–1000 µM, with a limit of detection (LOD) of 2.13 µM. For AA, the linear range was determined to be 5–40 µM, with a calculated LOD of 0.15 µM. This work not only demonstrates the potential of peroxidase-like nanozymes for sensing applications but also provides a valuable reference for the design and synthesis of MOF-based nanozymes.