Facile preparation of urchin-like NiCo₂O₄ microspheres for efficient hydrogen peroxide detection

In this work, urchin-like NiCo₂O₄ microspheres were prepared via a facile ionic liquid-assisted hydrothermal synthesis and used as non-enzymatic H₂O₂ sensors for the first time. The porous structure and high surface area of the NiCo₂O₄ microspheres provide plentiful active sites for electrocatalytic H₂O₂ oxidation. When adapted into an electrochemical sensor for H₂O₂, the microsensors showed fast response of 4 s, a high sensitivity of 392.5 μA·mM^-1 cm^-2, and a wide linear range towards H₂O₂ (0-14 mM). The detection limit was as low as 0.05 μM, significantly lower than other published high performance NiCo₂O₄-based H₂O₂ sensors. Furthermore, this non-enzymatic sensor exhibits good selectivity for H₂O₂. These results suggest that NiCo₂O₄ microspheres could be a promising material for trace H₂O₂ detection.