Enhanced photocatalytic activity of V2O5/g-C3N4/ZnO nanocomposite for efficient degradation of amoxicillin, chlorpyrifos and methylene blue

In the present research investigation, a novel nanocomposite viz. V 2 O 5 /g-C 3 N 4 /ZnO was synthesised using wet impregnation technique. Its photocatalytic degradation performance was assessed against various organic pollutants including the antibiotic amoxicillin (AMX), the pesticide chlorpyrifos (CPF) and the dye methylene blue (MB), under the effect of visible light in an aqueous medium. The materials synthesised and their photodegradation effectiveness were systematically characterised by a variety of techniques including XRD, HR-SEM, TEM, EDS, XPS, UV-DRS, PL, BET and EIS. XRD spectra confirmed the existence in the hexagonal phase of g-C 3 N 4 , the hexagonal wurtzite structure in ZnO and the orthorhombic phase in V 2 O 5 . The corresponding plane in the V 2 O 5 /g-C 3 N 4 /ZnO nanocomposite was also identified. The HR-SEM images depicted a composite of nanosheets and nanorods within the nanocomposite. The synthesised photocatalyst revealed an effective visible light absorption with a bandgap of 2.5 eV. The synthesised photocatalyst demonstrated impressive photocatalytic degradation efficiencies with an initial organic pollutant concentration of 10 ppm, in an acidic condition (pH 6), along with a catalyst dose of 50 mg under visible light exposure for 90 min. The degradation efficiencies were 97.3% for MB, 80.1% for CPF and 72.1% for AMX. This proved its higher efficiency than that of individual components viz. g-C 3 N 4 , ZnO and V 2 O 5 . The hole (h + ) and superoxide radical (O 2 ·−) were found to be the key reactive species, which are involving in the photodegradation process by radical scavenging tests. Furthermore, the present nano photocatalyst proved its remarkable photocatalytic stability even after three cycles, showing its favorable chemical properties. These findings imply that this reported photocatalyst is highly suitable for efficiently photodegrading the organic pollutants in aqueous environments. Graphical Abstract