Novel CoV₂O₆/g-C₃N₄ nanocomposite for efficient bifunctional electrocatalysis and high-performance electrochemical biosensing

Driven by the dual need for clean energy and sensitive biosensing platforms, this study explores bifunctional electrocatalytic and biosensing capabilities of cobalt vanadate (CoV₂O₆) and its novel nanocomposites with graphitic carbon nitride (g-C₃N₄). The materials were synthesized via an insitu co-precipitation method and confirmed through structural and spectroscopic analyses. Pristine CoV₂O₆ exhibited a distinctive stacked biscuit-like morphology, while the composites revealed strong interfacial interactions between both components. Among the samples, those with optimized g-C₃N₄ content displayed enhanced electrochemical active surface area (ECSA) and superior bifunctional electrocatalytic activity. Specifically, 20 % g-C₃N₄/CoV₂O₆ composite achieved a low overpotential (η) of 153 mV for oxygen evolution, while the 40 % g-C₃N₄/CoV₂O₆ composite required only 178 mV for hydrogen evolution and excelled in ascorbic acid biosensing with high sensitivity, stability, and reproducibility in commercial samples and different food extracts. The integration of CoV₂O₆ with g-C₃N₄ significantly improved carrier mobility and reaction kinetics, making these nanostructured composites highly promising for energy conversion and electrochemical (EC) diagnostics.