Enzymeless electrochemical detection of hydrogen peroxide using NiO octahedron decorated 3D graphene hydrogel

Nowadays, electrochemical biosensors have gained extensive consensus to detect a wide variety of analytes such as hydrogen peroxide (H₂O₂), glucose, dopamine, uric acid, and so on. However, the detection of H₂O₂ is more and more important because H₂O₂ plays a vital role in our daily life. Hence, a new nonenzymatic H₂O₂ biosensor was developed by decorating NiO octahedrons on the 3-dimensional graphene hydrogel (3DGH). The NiO octahedrons were prepared using a mesoporous silica SBA-15 as a hard template. Then, different amounts of NiO octahedrons self-assembled with 3DGH during hydrothermal method. The performance of different prepared nanostructures as H₂O₂ biosensors electrodes was determined by the cyclic voltammetry and chronoamperometry tests. Various physicochemical methods such as FE-SEM, HR-TEM, XRD, TGA and Raman were utilized to characterize the morphology and structure properties of the as-prepared samples. The electrochemical sensing of H₂O₂ for the proposed biosensor electrodes are investigated, and the 3DGH/NiO nanocomposite electrode with NiO content of 25% displays high sensitivity with wide linear range and low detection limit, as well as good selectivity, reproducibility and long-term stability. Finally, the analytical utilities of the 3DGH/NiO25 proposed electrode were conducted to detect H₂O₂ in real products of milk samples.