Electrochemical sensing of metronidazole using a dual-function V2O5/MgMn2O4/g-C3N4 catalyst with auxiliary photodegradation capability

Herein, a novel bifunctional V 2 O 5 /MgMn 2 O 4 /g-C 3 N 4 (VMCN) heterojunction nanocomposite was successfully fabricated via a facile ultrasonication-assisted hybridization method for photocatalytic removal of hazardous pollutants and electrochemical sensing of pharmaceutical products. Under the irradiation of visible light for 30 min, the VMCN composite showed excellent results, obtaining over 95 % efficiency for integrated adsorption degradation removal of Congo Red (CR), Eosin Yellow (EY), and Rose Bengal (RB) in the presence of H 2 O 2 . The high degradation efficacy was supported by detailed kinetics studies with a high rate constant of above 0.1 min −1 , and a low half-time, along with the double Z scheme charge transfer pathway. The degradation pathway of the pollutants was also analyzed through LC-MS analysis to recognize the reaction intermediates. Furthermore, the VMCN nanocomposite was modified on a glassy carbon (GC) electrode for the electrochemical detection of metronidazole (MNZ). The VMCN/GC electrode showed excellent electrochemical functionality with an LOD of 1.02 μM, a linear range of 25–250 μM, and a sensitivity of 8.25 × 10 −7 A/μM/cm 2 . The fabricated sensor was highly reproducible up to 11 cycles with an RSD of 5.61 % and showed a minimal current reduction in the presence of interfering species, demonstrating its high stability and selectivity. Additionally, real water analysis was also carried out to examine the sensor's accuracy in tap, lake, and sewage water for practical application. Hence, this work signifies the potential of VMCN nanocomposites as a versatile and robust material for pollutant removal and detection, contributing to overall environmental remediation. • Ultrasonication-assisted hybridization method for synthesis of V 2 O 5 /MgMn 2 O 4 /g-C 3 N 4 (VMCN). • The heterojunction exhibited dual functionality with enhanced performance. • Removal of 3 different classes of dyes with high efficiency and reaction rate. • Double Z-scheme photocatalytic mechanism was proposed for the charge transfer pathway. • VMCN/GCE displayed excellent electrochemical sensing performance for MNZ antibiotic drug.