Effect of Cynara scolymus extract concentration on the synthesis of ZnO semiconductor nanoparticles and their photocatalytic performance in the degradation of Rhodamine B, Methylene Blue, Methyl Red, Methyl Orange, Amino Black, and Alizarin Yellow

<jats:sec> <jats:title>Abstract</jats:title> <jats:p> Zinc oxide nanoparticles were synthesized through a green chemistry route using <jats:italic>Cynara scolymus</jats:italic> extract. FTIR spectra confirmed Zn–O stretching vibrations along with residual organic functional groups from the extract. UV–Vis analysis indicated band gap energies ranging from 2.87 to 2.95 eV, confirming the semiconductor behavior of ZnO. XRD analysis revealed the hexagonal wurtzite phase with crystallite sizes decreasing from 53.1 to 36.3 nm as extract concentration increased. SEM micrographs revealed aggregated ZnO nanoparticles forming irregular clusters with rough surface morphology, a feature commonly observed in plant-mediated green synthesis. Photocatalytic performance was evaluated against six dyes: Rhodamine B, Methylene Blue, Methyl Red, Methyl Orange, Amino Black, and Alizarin Yellow. The ZnO sample synthesized with 5% extract exhibited the highest degradation efficiency, achieving &gt; 90% degradation of Rhodamine B and Amino Black. These findings demonstrate the potential of <jats:italic>C. scolymus</jats:italic> mediated ZnO NPs for sustainable wastewater treatment applications. </jats:p> </jats:sec> <jats:sec> <jats:title>Graphical abstract</jats:title> </jats:sec>