Bandgap engineering of novel Cu-vanadate/g-C₃N₄ hierarchical nanoflowers for enhanced photodegradation and excellent biosensing capability

Copper vanadate and graphitic carbon nitride (g-C₃N₄) are pivotal materials in the realm of advanced materials science, owing to their distinctive optical and electronic conductive properties. In the context of environmental photocatalysis and biosensing applications, their synergistic combination holds significant promise. Copper vanadate, renowned for its optical and electronic properties, complements the unique architecture and optical conduction characteristics of g-C₃N₄. Together, these materials exhibit immense potential for driving advancements in environmental sustainability and diagnostic techniques. In this study, we report the synthesis of copper vanadate (Cu_0.261V₂O₅) and its composite with graphitic carbon nitride. XRD confirms the synthesis of the novel phase, FESEM and TEM analysis reveals hierarchical nanoflowers and UV-Visible spectroscopy divulges the visible light activation of the synthesized material and aids in the calculation of the optical bandgap. Interfacial charge transfer was studied with the help of EIS and Mott-Schottky analysis was employed to reveal the semiconductor type (n or p type) and determine the band edges. The as-prepared material was tested for the photocatalytic removal of methylene blue (MB), followed by the study of reaction kinetics, cyclic stability and active radicals participating in the photocatalysis process. The synthesized heterojunction showed 100 % removal of MB within a tenure of 90 minutes. The results of the experiment revealed that Cu_0.261V₂O₅ decorated with g-C₃N₄ displays 1.5 and 1.4 times better photocatalytic degradation capability than pure Cu_0.261V₂O₅ and g-C₃N₄, respectively. Furthermore, the synthesized material was evaluated for electrochemical biosensing of ascorbic acid in PBS (pH 7) analyte using a 3-electrode system. Compared to the pure material, the heterojunctions drew 1.9 times more current and provided near unity correlation (R²). It is evident that Cu_0.261V₂O₅ decorated with g-C₃N₄ can be implemented for commercial eco-remediation and electrochemical ascorbic acid sensing.