Unveiling the photocatalytic activities of morphology-controlled ZrO2, BaO, and Y2O3 nanoparticles using Eucalyptus leaf extract

Abstract

This study investigates the synthesis of transition metal oxide nanoparticles, including Zirconium oxide (ZrO₂), Barium oxide (BaO), and Yttrium oxide (Y₂O₃), using Eucalyptus leaf extract as a green reducing agent through a sonication-assisted approach. The nanoparticles were thoroughly characterized for their crystalline structure, functional groups, morphology, and elemental composition. The results confirmed the successful formation of distinct metal oxide bonds and unique morphological features: ZrO₂ exhibited semi-spherical shapes, BaO showed monodisperse spherical morphology, and Y₂O₃ displayed a flaky non-spherical structure. The photocatalytic activity of the nanoparticles was evaluated for the degradation of Brilliant Blue (BB) and Rhodamine B (RhB) dyes. Among the samples, BaO nanoparticles achieved the highest degradation efficiency, reaching up to 99 % for both dyes under natural sunlight. Antibacterial studies revealed significant activity, with BaO exhibiting 18 mm and 21 mm inhibition zones against E. coli and S. aureus. Real-time turbidimetric growth inhibition tests further demonstrated BaO’s superior performance, with growth inhibition rates of 81.4 % and 88.6 % against E. coli and S. aureus. Additionally, antioxidant activity assessed through the DPPH assay indicated that BaO nanoparticles exhibited the highest radical scavenging ability, surpassing ZrO₂ and Y₂O₃. These findings underscore the multifunctional capabilities of BaO nanoparticles, particularly in environmental remediation applications such as dye degradation, antibacterial treatments, and antioxidant activity, highlighting their potential for sustainable and eco-friendly solutions to pressing biological and ecological challenges.