Design and synthesis of multilevel structured Co3O4 double-shell dodecahedron as non-enzymatic electrochemical sensor for H2O2 detection

In this work, we used ZIF-67 as a template to prepare multilevel structured Co₃O₄ with a high surface area. The synthesized materials were characterized by SEM, TEM, XRD and N₂ physisorption.The double-shell dodecahedron multileve structure of Co₃O₄ (DS Co₃O₄) was found to have the most favorable morphology and largest specific surface area, and was demonstrated to be an effective electrochemical non-enzymatic H₂O₂ sensor. The efficiency is due to the unique multilevel structure of DS Co₃O₄, providing abundant active sites for H₂O₂ oxidation. The sensor showed a fast response time of 5 s, a high sensitivity of 1168.9 µA·mM^{− 1}cm^{− 2} and a detection limit of 0.048 µM (S/N = 3) in the linear range 0.0005–10 mM, significantly better than other reported high performance Co₃O₄-based H₂O₂ sensors. The as-fabricated DS Co₃O₄/RDE materials are promising sensors for H₂O₂ due to their excellent sensitivity, selectivity and long-term stability.