Ni foam-supported ZnO nanowires and Co₃O₄/NiCo₂O₄ double-shelled nanocages for efficient hydrogen peroxide detection

Nanocrystalline transition metal oxides have attracted a great deal of attention due to their good electrochemical activity. To pursue novel active electrode materials with low detection, high sensitivity and good selectivity for the detection of H₂O₂, Ni foam-supported ZnO nanowires and Co₃O₄/NiCo₂O₄ double-shelled nanocages (ZnO/Co₃O₄/NiCo₂O₄/Ni foam) have been successful fabricated by facile and effective methods When tested as an enzymatic-free H₂O₂ electrochemical sensor, the obtained ZnO/Co₃O₄/NiCo₂O₄/Ni foam exhibits fast response time within 5 s, low detection limit of 0.163 μM (S/N = 3), high sensitivity of 0.388 mA[rad]mM⁻¹ cm⁻², wide linear range from 0.2 μM to 2.4 mM (R² = 0.996), exhibiting good selectivity and long-term stability. The reason is that special structure of the ZnO nanowires could provide direct electrical pathways for the fast electron transport and Co₃O₄/NiCo₂O₄ double-shell nanocages provide abundant mesopores and large specific surface area to enhance the catalytic activity of H₂O₂ detection. These results suggest that the ZnO/Co₃O₄/NiCo₂O₄/Ni foam could be considered as a promising electrode material to build electrochemical biosensor.