Green synthesis of ZnO nanoparticles using Passiflora incarnata extract: Study of structural, morphological, optical, and photocatalytic properties for organic dye degradation

Abstract Zinc oxide (ZnO) nanoparticles were synthesized via a green approach using Passiflora incarnata extracts (1, 3, 5%) to evaluate the effect of precursor concentration on their physicochemical and photocatalytic properties. UV–Vis spectroscopy revealed an absorption peak at 367 nm, with bandgap values decreasing from 2.90 to 2.58 eV as the extract concentration increased. XRD confirmed the zincite phase with crystallite sizes of 30.13, 15.68, and 11.55 nm, while FTIR identified phytochemical functional groups and Zn–O stretching. SEM–EDS showed semi-spherical nanoparticles with moderate agglomeration and extract derived organic residues. Photocatalytic degradation of six dyes under UV irradiation for 180 min demonstrated variable efficiencies: enhanced performance for MO (80.67%), AB (92.06%), AY (80%) and MR (73.48%), but reduced activity for RhB (43.25%) and MB (57.04%) at higher extract concentrations. These results highlight the potential of Passiflora incarnata mediated ZnO nanoparticles as efficient, ecofriendly photocatalysts for wastewater remediation. Graphical abstract