In this study, zinc oxide hierarchical nanostructures (ZnO HSs) were successfully synthesized using a cost-effective, sunlight-assisted precipitation method at 1, 2, and 3 h (Z1, Z2, and Z3). Structural characterization by XRD confirmed the formation of pure ZnO with a wurtzite crystal structure, with a noticeable increase in crystallite size as the reaction time increased. FE-SEM results revealed that the ZnO HSs developed into distinct urchin-like hierarchical structures at longer synthesis durations. Elemental composition was confirmed through EDX, while FTIR analysis showed characteristic Zn–O bonding. Optical properties assessed by UV–Vis spectroscopy indicated strong absorbance in the UV region. PL spectroscopy revealed two emission peaks in the ultraviolet region and the visible region of the electromagnetic spectrum. The photocatalytic activity of the synthesized ZnO HSs was evaluated by the degradation of methylene blue (MB) dye under natural sunlight. The Z2 sample demonstrated the highest photocatalytic efficiency, with 93 % photodegradation in 60 min and a kinetic rate constant of 0.043 min⁻¹ . These findings highlight the remarkable potential of ZnO HSs for environmental applications. • Sunlight-assisted synthesis: ZnO HSs were synthesized via an eco-friendly sunlight precipitation method. • Morphology evolution: Longer sunlight exposure (1–3 h) formed well-defined urchin-like ZnO architectures. • Structural/optical integrity: XRD showed wurtzite ZnO; FTIR/EDX confirmed Zn–O bonding and stoichiometry. • Photocatalysis: 2 h ZnO achieved 93 % MB degradation in 60 min under natural sunlight. • Sustainable application: Low-cost green route to efficient photocatalysts for solar-driven environmental remediation.
Nusseif et al. (Fri,) studied this question.