Three-dimensional NiO/Co₃O₄@C composite for high-performance non-enzymatic glucose sensor

Area of Science:

• Electrochemistry
• Materials Science
• Biosensors

Background:

• Enzyme-free glucose sensors offer an alternative to traditional enzyme-based methods, potentially reducing costs and improving stability.
• Transition metal-based composite materials are being explored for their catalytic properties in electrochemical sensing applications.
• Developing robust and sensitive glucose detection methods is crucial for diabetes management and biomedical research.

Purpose of the Study:

• To construct and characterize a novel enzyme-free glucose sensor based on a two-dimensional NiO/Co3O4@C heterojunction.
• To evaluate the electrochemical performance, including sensitivity, selectivity, and stability, of the developed sensor.
• To demonstrate the sensor's applicability for glucose determination in real biological samples, such as serum.

Main Methods:

• Synthesis of NiO/Co3O4@C heterojunctions via pyrolysis of NiO@ZIF-67.
• Fabrication of the enzyme-free glucose sensor by modifying a glassy carbon electrode (GCE) with the synthesized composite material (Nafion/NiO/Co3O4@C/GCE).
• Electrochemical characterization using cyclic voltammetry (CV) and chronoamperometry (i-t curve) to assess sensor performance.

Main Results:

• The NiO/Co3O4@C composite exhibited excellent electrocatalytic activity for glucose oxidation.
• The fabricated sensor demonstrated wide linear ranges (5-1000 μM and 1.0-4.0 mM) with high sensitivities (690 and 215.4 μA mM⁻¹ cm⁻²).
• A low detection limit of 2.28 μM (S/N=3) and high recovery rates (98.9-99.7%) in real samples were achieved, indicating excellent accuracy and reliability.

Conclusions:

• The developed enzyme-free glucose sensor based on Nafion/NiO/Co3O4@C/GCE exhibits superior electrocatalytic properties, reproducibility, stability, and anti-interference capabilities.
• The sensor successfully detected glucose in real serum samples, highlighting its practical potential for clinical diagnostics.
• This work presents a promising strategy for developing advanced electrochemical sensors using transition metal-based composites for biomedical applications.