H2O2-Assisted Sunlight Photocatalytic Degradation of Basic Fuchsin Using Green-Synthesized ZnO Nanowires

The efficient removal of toxic dyes from wastewater remains a major environmental challenge. In this study, we report a green and facile one-pot synthesis of zinc oxide nanowires (ZnO-NWs) using lemon verbena leaf extract as a sustainable capping and stabilizing agent. The extract played a vital role in directing the 1D growth of the wurtzite hexagonal structure. Characterization confirmed a band gap of 3.12 eV and the characteristic Zn-O stretching at 375 cm−1. Photocatalytic activity tests using 20 mg of biosynthesized ZnO-NWs demonstrated excellent degradation performance. A rate constant of 0.0067 min−1 was achieved, with 99.95% degradation of Basic Fuchsin under natural sunlight for 3 h. Active species analysis highlighted the crucial roles of holes (h+), superoxide radicals (O2•−), and hydroxyl radicals (•OH). Notably, the addition of 10 mM H2O2 produced a powerful synergistic effect, reducing the degradation time from 3 h to only 7 min and increasing the reaction rate by approximately 25-fold. These findings highlight the potential of biosynthesized ZnO-NWs as highly efficient, rapid, and sustainable photocatalysts for environmental remediation.