A novel enzyme-free glucose and H₂O₂ sensor based on 3D graphene aerogels decorated with Ni₃N nanoparticles

In this work, a novel enzyme-free glucose and hydrogen peroxide (H₂O₂) sensor based on Ni₃N nanoparticles on conductive 3D graphene aerogels (Ni₃N/GA) has been successfully synthesized by using hydrothermal reaction, freeze-dried and then calcined under NH₃ atmosphere. The obtained Ni₃N/GA composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption-desorption isotherms and electrochemical methods. The results show the obtained 3D Ni₃N/GA composites exhibit excellent electrochemical performance toward glucose oxidation and H₂O₂ reduction with larger catalytic rate constant K_cat value of 3.75 × 10³ M^-1 s ^-1 and 1.24 × 10³ M^-1 s ^-1, respectively. As a glucose sensor, the obtained electrode provides a wide detection range of 0.1-7645.3 μM, fast response time within 3 s, high sensitivity of 905.6 μA mM^-1 cm^-2 and low detection limit of 0.04 μM. For detection of H₂O₂, this prepared sensor offers a wide detection range (5 μM-75.13 mM), fast response time (within 5 s), sensitivity (101.9 μA mM^-1 cm^-2) and low detection limit (1.80 μM). This enzyme-free glucose and H₂O₂ sensor display satisfactory selectivity, reproducibility and long-term storage stability. Additionally, the sensor can also be used for glucose and H₂O₂ detection in human blood serum. The results demonstrate that 3D GA nanostructures provide an enviable conductive network for efficient charge transfer and avoid Ni₃N nanoparticles aggregation, which is advantageous for electrocatalytic applications.